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The Horse and Burro as Positively Contributing Returned Natives in North America

  • International Union for Conservation of Nature, Andean Tapir Fund


Since the Wild Free-Roaming Horses and Burros Act of 1971, debate has raged over whether horses and burros are restored North American natives. Fossil, genetic and archeological evidence supports these species as native. Also, objective evaluations of their respective ecological niches and the mutual symbioses of post-gastric digesting, semi-nomadic equids support wild horses and burros as restorers of certain extensive North American ecosystems. A Reserve Design strategy is proposed to establish naturally self-stabilizing equine populations that are allowed to harmoniously adapt over generations within their bounded and complete habitats. These populations should meet rigid standards for viability based on IUCN SSC assessments (2,500 individuals). Basic requirements are described for successful Reserve Design including viable habitat as well as specific regions of North America where this could be implemented.
American Journal of Life Sciences
2013; X(X): XX-XX
Published online MM DD 2013 (
doi: 10.11648/j.XXXX.2013XXXX.XX
The Horse and Burro as Positively Contributing Returned
Natives in North America
Craig C. Downer
A.B., M.S., Ph.D. Candidate., Andean Tapir Fund, P.O. Box 456, Minden, NV 89423-0456 USA
Email address:
Abstract: Since the Wild Free-Roaming Horses and Burros Act of 1971, debate has raged over whether horses and
burros are restored North American natives. Fossil, genetic and archeological evidence supports these species as native.
Also, objective evaluations of their respective ecological niches and the mutual symbioses of post-gastric digesting, semi-
nomadic equids support wild horses and burros as restorers of certain extensive North American ecosystems. A Reserve
Design strategy is proposed to establish naturally self-stabilizing equine populations that are allowed to harmoniously adapt
over generations within their bounded and complete habitats. These populations should meet rigid standards for viability
based on IUCN SSC assessments (2,500 individuals). Basic requirements are described for successful Reserve Design
including viable habitat as well as specific regions of North America where this could be implemented.
Keywords: Equidae, Wild Horses and Wild Burros, Horse and Burro Evolution, Horse and Burro Ecology,
North American Native Fauna and Ecosystems, Reserve Design,
Wild Free-Roaming Horses and Burros Act of 1971
1. Introduction
All branches of the horse family (Equidae) share an
ancient evolutionary origin and long-standing duration in
North America, having evolved here for ca. 60-million
years ago. Few other mammalian families can lay as much
claim to native status and belonging on this continent. Two
other extant families in the Order Perissodactyla are the
tapir and the rhinoceros families, and both are similarly
rooted in North America. From George Gaylord Simpson1
to Bruce MacFadden2, various scientists have described the
horse family's fascinating story; and their works reveal the
ascent of many distinctive yet interwoven equine genera
and species over the eons. The horse family has branched
out to all continents except Australia (prior to the arrival of
whites) and Antarctica. These animals have contributed
positively to our planetary communities, and they continue
to do so in many ways and on many levels today.
The rapid reoccupation of vacant niches in North
America by the horses (Equus caballus) and burros (Equus
asinus) may be viewed as corroborating their return to
ancestral grounds. In the words of the Plains Indians: ‘The
grass remembers the horses.’
In this article, I present evidence for the origin and long-
standing evolution of both horse and burro evolutionary
branches in North America, and further support the entire
horse family as primarily native here. I go on to show that
both horses and burros are returned native species and
merit protection. In complementary fashion, I also describe
the unique ecological roles filled by horses and burros,
explaining how they both preserve and restore native
ecosystems in the American West. Finally, I propose
reserve design as a means by which wild horses and burros
can restore themselves as vital components of viable
ecosystems and be truly protected as mandated by the Wild
Free-Roaming Horses and Burros Act of 1971. I also
suggest regions where this could be possible.
2. Methods
I gathered information for this article through a thorough
literature review of the history, evolution, ecology, and
conservation of wild horses and burros in North America.
This review has been a life-long one and accompanied by
visits to and observations of many of the wild horse and
burro herds and occupied habitats throughout the western
United States. This has resulted in a graduate paper on the
behavior and ecology of the Pine Nut Range wild horse
herd of western Nevada and other reports and publications.
The sources for this article are listed in the references
I have attended several professional conferences
concerning wild horses and burros and other wildlife at
which I have presented papers, e.g. International
Interdisciplinary Environmental Conference 2013,
International Equine Conference 2011 and 2012, Wild
Horse Summit 2008, and Wild Horse Forum 1980. Material
from these papers has been incorporated into this article.
Professional consultation with professors, biologists, and
government officials has also guided the preparation of the
article. Many of the points presented here were also
presented in my book The Wild Horse Conspiracy.3 My
extensive research on wild equids and other perissodactyls
has resulted in scientific publications, including
encyclopedic articles (e.g. Grzimek’s, 2004), a species
resume and action plan[4], and scientific journal articles, as
well as many popular reports and articles. These have
described the evolution, ecology, and conservation history
and plans past, present, and future of perissodactyla
species, including the endangered mountain tapir as well as
the wild horses and burros of North America.
Characteristics common to the order include a mesaxonic
weight-bearing, odd-toed anatomy, possession of both
upper and lower incisors permitting careful pruning of
vegetation, and the possession of a post-gastric (in contrast
to a pre-gastric, multi-stomach ruminant) digestive system.
These and other shared characteristics place members of
the horse, tapir, and rhinoceros families into similar
ecological niches and roles. A knowledge of these
characteristics affords insight concerning contributions to
the North American ecosystems by both horse and burro
lineages evolving here since the early Cenozoic Era ca. 60
MYA. This knowledge relates a wider variety of species,
genera and families that share near-lying branches on the
“family tree” of life expanding over time. And this
knowledge has greatly aided me in composing this paper.
3. Findings and Discussion
3.1. Evidence of the Long-Term Presence and Evolution
of Horses and Burros in North America
3.1.1. Yukon Horse substantiates North American Origin
of Modern Horse. During the mid-1990s, horse remains
were discovered by placer miners in the Yukon. They were
well preserved in the permafrost and seemed to have died
recently, yet proved to be approximately twenty-five
thousand years old. Their rufous color, flaxen mane and
solid hooves had the aspect of a typical, small and wiry
mustang of the West. Based on external morphology, the
specimen was identified as a “Yukon horse,whose Latin
name is Equus lambei. Intrigued, paleontologists conducted
a genetic analysis of this specimen, which showed it to be
one and the same as the modern horse: Equus caballus.
Further independent analysis conclusively proved this.
With this substantiation came a more widespread
recognition of wild horses as returned native species in
North America, since E. lambei was seen to be identical to
E. caballus[5].
Carbon-14 datings of mitochondrial DNA (passed along
the maternal line) have been meticulously analyzed by Dr.
Ann Forsten[6] and have substantiated the origin of the
modern horse in North America at 1.7 MYA (million years
ago). According to Forsten: “[t]he early branching-off time
indicated by mtDNA supports an origin of the caballoids
[the horse branch of the horse family: Equidae] in the New
World, and the fossil record suggests an even rather late
dispersal to [the] Old World.”5
The fact that the Yukon horse is genetically identical
with the modern horse reveals the latter to be one of the
most deeply rooted and justifiable native species in North
America. This native status is additionally substantiated by
the species’ large geographic distribution upon this
continent that is evident from the fossil record and the great
variety of ecosystems in which it can adapt and live.
Furthermore, though the modern horse traces back ca. 2
million years in its present form, it should actually be
regarded as part of the continuous context of equid
evolution that dates back at least 58 million years in North
3.1.2 More Recent Horses in North America. A
considerable body of evidence has surfaced concerning the
more recent survival of the horse species in North America.
Though the prevailing view maintains that the entire horse
family died out around 10,000 years ago at the end of
Earth's last major glaciation, evidence for horse presence
from anywhere from a little over 7,000 years before present
(YBP) to less than 1,000 YBP is too substantial to dismiss.
[8]. Among other lines of evidence, this comes in the form
of fossil bones that have been age-dated to more recent
times, horse geoglyphs (ground drawings) dated to about
1,000 years ago,[9] and petroglyphs, or stone depictions.
Figure 1. Horse petroglyph discovered by author west of White
Mountains, eastern California. (Photo by author.)
The FaunMap produced and published by the Illinois
State Museum of Springfield, revealed a number of horse
fossil datings within the post-Pleistocene-Pre-Columbian
period that occurred well after the time at which all
members of the horse family are commonly believed to
have disappeared from North America. Some of these are
quite close to Columbus' discovery of America in 1492.[10]
(See section 3.2)
3.1.3. Petroglyphs and Geoglyphs. During the summer of
2002, I visited the austere White Mountains east of the
towering, snow-capped Sierra Nevada near Bishop,
California. The ancient White Mountains rise to over
13,000 feet at Boundary Peak and contain one of the most
ancient life forms on Earth: the majestic, die-hard
Bristlecone Pine, one of which has been dated to near 9,000
years of age.[11] Intrigued by this atmospheric region on
the edge of eastern California and western Nevada, I went
on to explore the desert valley just to the west of these
mountains. Here I came upon some fascinating
petroglyphs dating from modern times to a few thousand
years ago (Bureau of Land Management, Bishop California
office, pers comm.). These artful designs had been
painstakingly chiseled with hard tools on granite to form
hypnotizing spirals, geometrical checkerboards,
arrowheads, lances, strange anthrozooic (man-animal)
figures, eagles, bighorn sheep with large, curved horns, and
then, much to my amazement, a definite horse figure,
without apparent rider, bridle, rope or saddle, rendered in
simple rectilinear fashion but with proportions
unmistakably those of a horse (see Figure 1). Judging from
the brownish oxidation on the chiseling, this horse was not
a recent addition to the ancient petroglyphs here. Scientific
analysis of the patina of some of these petroglyphs has
revealed ages up to 3,000 years. By visually comparing
patina hues, I estimated this horse could be well over 1,000
years old.
Joseph revealed geoglyphs depicting horses in the
Mojave Desert near Blythe in southeast California.7 These
were also featured in another scholarly work as an eight-
meter horse geoglyph pictured alongside a 25-meter
human.[9] There are two horses among these several
geoglyphs, collectively known as the Blythe Giants and
representing the Earth Figure Tradition, which overlaps
with the Great Basin Tradition. They were formed by
removing stones of desert pavement to reveal lighter
substrata, a process called intaglio, often associated with
trails and dance circles formed by the pounding of human
feet. They indicate that horses were held in high regard by
Amerindians and in relatively recent times. The figures
have been expertly dated by geologists from the University
of California-Berkeley at 900 A.D. +/- 100 years and were
first discovered by pilots from the U.S. Army Air Corps
flying between Hoover Dam and Los Angeles in 1932.
They are presently under the care of the Bureau of Land
Management. As Joseph puts it: “[t]his [figure] meant that
someone in California knew enough about the horse to
represent it on the desert floor … centuries before the
Spaniards re-introduced the animal to North America.”[9]
Though airline pilots and later observant investigators and
writers have instantaneously recognized this figure as a
horse, BLM officials claim it depicts a puma and have
restricted the public from accessing the area and deciding
for themselves (see Fig. 2).
Figure 2. Horse geoglyph, Mojave Desert, southeast California, dated to
about 900 years ago.[9]
3.2. Fossil Evidence
3.2.1. Shield Trap Fossil Site. One of the most
convincing series of finds comes from the Shield Trap
fossil site located in Carbon County, Montana.[10] This is
located on the east Pryor Mountain quadrangle (7.5 minute
map) at Latitude 45.1167 degrees and Longitude 108.25
Here four strata have been excavated. In Stratum I, part
of the Late Holocene period, carbon dating from bone
collagen samples (collagen consisting of the fibrous
albuminoid component of bone) from two different horses
has yielded precise edge dates of 1745 and 1270 YBP. In
Stratum II, dating between 5490 and 2185 YBP, four
different individual horse dates have been obtained. Three
of these were again obtained from bone collagen, as well as
from cartilage and other connective tissue types. These
dated at 3190, 2675 and 2185 YBP. A fourth horse C-14
dating was done from charcoal associated with the fossil
and produced the extraordinarily young date of 620 YBP,
indicating the distinct possibility of horse presence in North
America just over a century prior to Columbus's arrival in
America. Though the latter was inconsistent with the date
of the soil of Stratum II, it is not uncommon for earth
movements or erosion to produce such mixing. If
contamination can be ruled out, this fossil could go a long
way toward proving the continuous occupation of North
America from ancient times to the arrival of Europeans and
the reintroduction of horses to North America.
In Stratum III of the Shield Trap fossil site, seven C-14
datings again revealed horse presence at later dates than is
recognized by mainstream paleontology. Stratum III
extends from 7540 to 5490 YBP and is in the Middle
Holocene period. C-14 dates obtained from charcoal from
five horses yielded dates of 7540, 7540, 7540, 7165 and
7165 YBP, while the two horse fossils that were C-14 age
dated from bone collagen yielded 7245 and 5490 YBP. The
5490 YBP age dating is remarkable and substantiates a later
survival of the horse in North America. Recently surfaced
DNA discoveries in soils in Alaska renew our credence in
horse presence in North America that is less than 8,000
years ago.[12]
The horse fossil series at Shield Trap gives solid
evidence for a continuous horse lineage from the time of
the “Great Die Out” at the close of the Pleistocene to
modern times, i.e., after the advent of Columbus and the
European colonization of the Americas. The area around
the site should be explored for additional fossils to further
substantiate these findings.
3.2.2. Other Intriguing Fossil Sites. Still another well-
confirmed series of dating for a horse fossil comes from the
Wolf Spider Cave in Colorado. These yield a date of 700
+/- 50 YBP and are clearly post-Pleistocene and pre-
Columbian and, again, not far before the arrival of
Columbus in 1492. The Wolf Spider horse was dated by a
professionally respected age-dater: Elaine Anderson. The
Pratt Cave fossil site in Texas has a horse fossil that has
been solidly dated to about ten times that of Wolf Spider, or
7080 +/- 40 YBP.
Many other sites yield horse fossils with scientific
datings that indicate more recent horse survival (see Figure
3). These datings range from the High Holocene (HIHO) 0
to 450 YBP, the Late Holocene (LHOL) 450 to 4500 YBP,
the Middle Holocene (MHOL) 3500 to 8500 YBP, and the
more catchall, early Holocene/middle Holocene (EMHO)
3500 to 10,500 YBP. (See Appendix for a partial list of
horse fossil sites).
3.2.3 Presence of the horse in Pre-Columbian and Post-
Pleistocene North America? The dates of 1,000 YBP or
less, such as from the Shield Trap fossil site and from Wolf
Spider and Little Box Elder caves, lend particular weight to
the hypothesis that remnant horses survived to the time of
the colonization of the Americas by Europeans. These
remnant survivors could have interbred with European-
derived horses, especially those escaped to the wild, the
denominated mostrencos (Spanish for “unclaimed”), or
mustangs. This is an intriguing possibility that should be
investigated using state-of-the-art genetic analysis – and
soon. To sum up, we have at least 50 different horse fossils
from 23 different sites including in the East, the West, the
North, and the South of the United States, as well as one in
South America. The majority of these indicate a much
wider horse distribution and at much later dates than is
commonly accepted by mainstream paleontologists today
(see Figure 3).
[For Frank, 1999, see reference 65 for Joseph, 1999 (I switched first for last name in this chart); for White, 2003, see reference 66.]
In addition to the above, several horse fossils have been
dated by association from the geological strata in which
they were found and also fall within the post-Pleistocene
and pre-Columbian period. They proceed from such
disparate areas as: (1) the Spencer and Laatch
Archeological Mount, Wisconsin; (2) Truman Reservoir,
Missouri; (3) the Hopewell Burial Mound, Ohio; (4)
prehistoric Indian kitchen middens of Arizona, ca. 3000
YBP;[13] and reportedly from (5) Winnemucca Lake Flats,
just east of Pyramid Lake, Nevada. Apparently the horse
fossil of Winnemucca Lake was discovered ca. 1978 and
dated to ca. 1,000 YBP by paleontologists at the University
of Nevada, though later all trace and record of this horse
fossil appear to have vanished under suspect circumstances
(Holland Hague, pers. comm. and documents in his
The myth of the destructive, non-native horse is rapidly
falling by the wayside, as people broaden their horizons in
regard to the horse's deeply rooted North American
presence and the many substantial contributions it makes to
the native ecosystem. An exciting analysis of the DNA
contained in the soils of permafrost regions of Alaska has
recently come to light proving that both horses and
mammoths were present in North America thousands of
years later than previously thought. This is a comeback to
what was espoused for decades by paleontologists, i.e.,
horse presence upon this continent to ca. 7,000 years ago.
An international team of scientists assembled at Camp
Stevens, Alaska, conducted this study, and its results are
most encouraging for those who sense the horse's true
belonging in North America.[12]
3.2.4. Suggestive Amerindian Evidence for Surviving
Native Horses. Suggestive evidence for more recently
surviving horses in North America is to be found in the
cultural knowledge of native tribes handed down from
generation to generation. Many of these oral histories have
their origin in pre-Columbian times. In her book: In Plain
Light: Old World Records in Ancient America, Gloria
Farley14 presents many illustrations indicating post-
Pleistocene, pre-Columbian horses in North America.
These include petroglyphs similar to the one I discovered
(Figure 1).
According to historian Claire Henderson15 of Laval
University, Quebec: “Traditional Dakota/Lakota (Sioux)
people firmly believe that the aboriginal North American
horse did not become extinct after the last ice ages and that
it was part of their pre-contact culture.” Though
established anthropological opinion has it that the Plains
Indians acquired horses in the early 1500s, as escaped or
stolen horses from Spaniards in Mexico and the
southwestern United States, the Sioux claim that the North
American horse survived the Ice Age and provided the
mounts for their ancestors long before Columbus's
discovery of America. They maintain that these distinctive
native ponies, in fact, continued to thrive on the North
American prairies until the first half of the 1800s “when the
U.S. Government ordered them rounded up and destroyed
to prevent Indians from leaving the newly created
reservations.” This massive slaughter is well documented.
Though much evidence backing the Sioux elders' claims
was destroyed along with the horses, some suggestive
evidence remains. For example, the Dakota/Lakota possess
different words for “horse,” thus distinguishing between the
sunkdudan, their own short-limbed horse, and the more
long-legged horse brought by Europeans. Sioux elders
whom Henderson consulted said that the aboriginal pony
stood about thirteen hands high (52 inches) and had a
straighter back, wider nostrils, and proportionately larger
lungs than European horses. Accordingly, these ponies
possessed even greater stamina and endurance than the
nonetheless remarkable horses brought from Europe.
Reports of shaggy hair and singed manes seem tarpan-like
and were confirmed by Prince Frederick Wilhelm of
Wurtemberg, Germany.17 Henderson ended her plea with a
call for the careful conservation of “the few remaining
Indian ponies.” I would add to this a call for a comparative
genetic analysis among germane horse populations to
determine if unique North American characteristics,
including mitochondrial and Y-chromosome DNA markers,
exist. In this connection, a search for possible remains of
slaughtered Plains Indian horses should be undertaken.
3.2.5. Suggestive Canadian Evidence. According to Dr.
Robert M. Alison, “the complete extirpation of ancestral
horse stock in Canada has yet to be confirmed and a
bone found near Sutherland, Saskatchewan, at the Riddell
archaeological site suggests some horses might have
survived much later. The bone (Canadian Museum of
Nature I-8581) has been tentatively dated at about 2,900
years ago. Another Equus species bone found at Hemlock
Park Farm, Frontenac County, Ontario, dates to about 900
years ago.”18 In his conclusion, Alison unequivocally states:
“... the main lineage originated on the North American
continent. Horses are therefore indisputably native fauna,
despite a multiplicity of genotypic variations.” In regard to
the reintroduced horse from the Old World, he continues
that “...subsequent evolution elsewhere over a period of
perhaps 8,000 years [does not] make them non-
indigenous.” He further observes that the “inherent
timidness of Canada's surviving free-ranging wild horses,
and genetic testing confirm [that] these animals do
not derive from escaped domestic Block farm/ranch stock”
and that “their shy behaviour is consistent with a long
history of sustained freedom ...”18 Dr. Alison, a biologist,
urges increased protection and resource provision for
Canada's last remaining wild horses as contributors to the
native North American biodiversity and warns of their
imminent disappearance. His testimony should greatly aid
many Canadians, including those of the Canadian Wild
Horse Foundation who are since July 2013 have been
trying to pass a law in Parliament to legally protect the
estimated less-than-1,000 wild horses still managing to
survive in spite of strong persecution from ranchers and
hunters in Alberta, Saskatchewan, and British Colombia.
3.2.6. The Asian Question. An intriguing line of
evidence that horses were present in America over 3,000
years before Columbus's arrival comes from Chinese
writings. One manuscript dating from 2,200 B.C. indicates
that the Chinese came to North America by sea at very
early dates and described several animals occurring in Fu
Sang, or the “Land to the East.” Their descriptions match
certain North American animals, including bighorn sheep
and horses resembling the appaloosa. Scholars question
whether this involves horses that were earlier brought by
the Chinese to North America and set loose, or horses that
were already living here and that were subsequently
captured and taken back to China. A distinctive gene (the
LP, or Leopard Pattern) has been identified in the patchy-
rumped appaloosa breed of horse, and research is now
underway to trace its origin. Perhaps this will substantiate
a uniquely North American horse characteristic. The idea
that the appaloosa originated in China is based on certain
appaloosan traits, mainly to do with coloration, that are
found in China; however, Chinese horses are generally
chunkier in build than North American appaloosas. This
poses a question concerning how this relates to Amerindian
beliefs about the stockier surviving native horses in North
America (see section 3.2.4).
Also of note: ca. 627-656 A.D. in the middle of China's
Golden Age (A.D. 581-907) during the reign of T’ang T’ai-
tsung (A.D. 618-649) and his successors Ching-Kwan and
Yung-Hwui, Chinese explorers traveled to Ta Han, or Da
Han, meaning “the land of the Great Giants.”19 The New
Book of Tang reports this land as rich in sheep (perhaps
referring to the bighorn or Dall sheep) and horses (see also
Harris Rees 201120).
3.3. The Case for the Burro
In similar fashion to the wild horse, the burro (Equus
asinus) can trace its not-far-removed ancestry back to
North America; and in many parts of this continent, wild
ass fossils testify to a very similar species occupying a very
similar niche as the one reoccupied by burros during the
past five centuries.
MacFadden indicates that the ass branch of Equidae
evolved in North America throughout the Hemphillian,
Blancan, and Pleistocene periods, when one Equus
mexicanus was clearly present.2 Though the modern burro,
or donkey, is currently considered as having originated
from African wild asses (Equus africanus) and can and
does produce fertile offspring with such,21 it is most
probably not significantly different from its North
American ancestors. Indeed, one respected paleontologist
believes that the African wild ass originally arose in North
America.22 And until recently both burro and African wild
ass were considered to be the same species, namely Equus
asinus which is still the case in many circles. Like the
wild horse, when returned to North America, the burro
readily adapts to an ecological niche that its not-so-distant
ancestors filled for millions of years, particularly in the dry
southwestern US and south into Mexico. The distinction
between E. asinus and E africanus seems more a political
than a sound biological one.
3.4. Two Hypotheses
In summary, much evidence exists for horse presence in
the Americas, especially North America, during the post-
Pleistocene and pre-Columbian period at dates scattered
through the period beginning ca. 10,000 YBP and reaching
very near to 1492 A.D. Two hypotheses have been
proposed to explain these apparent anomalies:
(1) A continuous lineage of horses survived in small
remnants up until the reintroduction of European
horses. When the latter escaped from or were released
by the Spanish, other Europeans, or Amerindians, they
thrived in the plains and southwestern deserts in the
very land of their evolutionary origin as a species and
reproductively intermingled with the already present,
aboriginal horses. Populations of these aboriginal
horses were absorbed by the greater influx of horses
brought over by colonists, conquistadors, etc., many
of whom derived from Spanish haciendas or Catholic
missions. The distinctively American traits of certain
wild horse populations lend support to this hypothesis
as do depictions of un-mounted horses au naturel in
geoglyphs and petroglyphs, some of which are dated
hundreds of years before the arrival of Columbus (see
Figures 1 & 2).
(2) Horses disappeared from North America during the
late Pleistocene ca. 10,000 – 7,000 YBP, but were
brought back to North America by other cultures in
pre-Columbian times. Possible cultures for which
evidence exists include: (i) Chinese immigrants in
junk ships hugging the coasts of the Pacific
Northwest; (ii) Scandinavians in long ships by way of
Greenland and landing in Newfoundland or Nova
Scotia, and (iii) other cultures, such as the Celts from
Wales or Ireland, or people in boats from southern
France who came clinging to the southernmost edges
of northern ice caps that had extended far to the south.
The latter left their distinctive form of spears in the
New World.
Regardless which of these two options is true or whether
a combination of such or some other option, after the
Spanish brought horses, beginning with Hernan Cortez in
the early 1500s, escapees and horses stolen by the Indians
began to repopulate the Americas to a large degree. These
could have reproductively intermingled with horses that
had been brought by other cultures in earlier times and/or
that were in North America originally. These horses likely
possessed a superiority over other races, a hybrid vigor
giving them survival advantages in the wild. This is all the
more reason for preserving the mustang herds in the wild
3.5. A Broader Perspective
Since shortly after the dawn of our present Cenozoic Era,
dating from the extinction of the dinosaurs ca. 65 MYA, the
ascent of all three major extant branches of the horse
family: zebras, asses, and caballine horses has taken place
primarily in North America.2
During the course of their long co-evolution, members of
the horse family developed many mutually beneficial
relationships with plants and animals. Indeed, both asses
and especially caballine horses can stake the claim to being
among the very most ancient and long-standing members of
the North American life community, more so than most
other large mammals still surviving here. For example,
among the bovid family both the bighorn sheep (Ovis
canadensis) and the bison (Bison bison) had their origins in
Eurasia before crossing over the “filter” Bering Land
Bridge, or isthmus, during the Pleistocene epoch 2-3 MYA.
This is when oceans receded with the tie-up of global
moisture during the ice ages. Thus, the later two species are
relative newcomers in North America when compared with
the horse and other members of the horse family. Members
of the deer family, Cervidae, including white-tailed and
mule deer, elk and moose, arose in Asia during the
Oligocene epoch 36-23 MYA and did not arrive in North
America until the Miocene epoch 23-7 MYA. They crossed
over the Bering Land Bridge to occupy North America.
Though their origin is more in the Old World, few
authorities would question their native status in North
America. Yet, many of these same persons will question
members of the horse family in this regard in spite of the
fact that all three extant branches of the Equidae: zebras,
asses and caballine horses had their origin and long-
standing evolution right here in North America, as an
abundant fossil record proves.
According to equid expert Dr. Hans Klingel, “... there is
evidence that all the extant equids [members of the
horse family] evolved as species on the North American
continent, and that Grevy's Zebra and the African and
Asiatic wild asses were the first to cross the Bering Bridge
in the early Pleistocene, whereas the remaining species
came to the Old World only during the late Pleistocene.
This would explain the much wider range of Grevy's zebra
in Africa during the Pleistocene, i.e., before their major
competitors, plains and mountain zebra, had arrived. It is
feasible that similar situations existed with respect to
African and Asiatic Zebras.”22
Also we need to consider that North America, Europe,
and North Asia share many faunal and floral elements, over
both their more recent and more distant evolutionary
histories. And equids, including horses and asses, figure
prominently in this sharing.26 Though often separated by
natural barriers, these three regions have experienced
frequent faunal and floral interchanges during periods when
barriers have either broken down, as through sea lowerings
or freeze-overs, or been overcome by the versatile and
persistent efforts of the animals themselves, including we
3.6. The Ecology of Wild Horses and Burros in North
Wild horses and burros complement North America's life
community in many direct and obvious as well as more
subtle ways. This they do when permitted their natural
freedom to move and interrelate over a sufficiently
extensive intact habitat and time period.3
3.6.1. Dietary Benefits, Building Soils, Dispersing Viable
Seeds. One obvious ecological relationship occurs between
diet and habitat. Including today's extant zebras, asses and
horses, all equids possess a caecal, or post-gastric, digestive
system. This is found in other perissodactyl families,
including tapirs and rhinoceroses, as well as other
mammalian orders. Such a system enables equids to eat
coarser, drier vegetation and, through symbiotic microbial
activity, to break down cellulose cell walls to derive
sufficient nutrients from the inner cell without overtaxing
their metabolism. In drier regions, this often gives a distinct
advantage over ruminant herbivores (those that have
multiple stomach chambers and chew the cud) whose pre-
gastric food processing requires expending considerably
more metabolic energy and taking in more water. While it
is true that equids must consume somewhat more
vegetation, especially when dry and coarse, because of their
less thorough extraction of nutrients from the food, this
usually does not overly deprive ruminants, since much of
what the equids consume would be of little or no value to
them. As a matter of fact, the equids’ consumption of this
coarser, drier vegetation can greatly benefit sympatric, pre-
gastric (ruminant) herbivores, and energize and enrich the
ecosystem as a whole. By recycling chiefly the coarse, dry
grasses as well as other dry, withered herbs, forbs and bush
foliage, the horses and burros expose the seedlings of many
diverse species to more sun, water and air, thus permitting
them to flourish. The latter can then be consumed by
ruminants, as British ecologist R.H.V. Bell has so well
demonstrated in his studies in the Serengeti.27
Also of great importance is the contribution by wild
equids of significant quantities of partially degraded
vegetation in the form of feces deposited on the land. These
droppings provide fodder for myriad soil microorganisms;
the resulting fecal decomposition builds the humus
component of soils, lending ecologically valuable texture
and cohesiveness. As feces slowly decompose, they
gradually release their nutrients over all seasons and, thus,
feed the fungal garden that exists in soils, thereby
increasing the soil's absorption of water a vital limiting
factor in semi-arid and arid regions. To reiterate: equid
feces are much more valuable to the health of soils than
ruminant feces (cattle, deer, sheep, goats, etc.) precisely
because they are not as decomposed when exiting the body
and, so, lend more sustenance to decomposers and food
webs that involve mutually sustaining exchanges among all
classes of organisms. The latter include many diverse
insects, birds, rodents, reptiles, etc. And, similarly, the less
degraded feces of equids contain many more seeds that are
intact and capable of germination and from many more
types/species of plants when compared with ruminant
grazers. Thus, the horses’/burros’ wide ranging life styles
greatly assist many plants in dispersing far and wide and,
so, in filling their respective ecological niches. This
enriches the food web and allows a greater diversity of
animal species.
3.6.2. Topography Enhances Habitat. Another germane
point concerns the multiplication of ecological niche space
that occurs in mountainous regions, with their accentuated
topography. This creates greater opportunities for plants
and animals to derive a living when compared with flatter
regions, because such terrain provides more surface area on
which to live. And perfect examples of such occur in the
Great Basin’s hundreds of mountain ranges where most of
America’s remaining wild horses have their legal areas. All
this argues for higher government-assigned population
levels, or Appropriate Management Levels (AMLs). As
shown in studies of the endangered mountain tapir of the
northern Andes inhabiting from 6,000 to 16,000 feet
elevation; steeper, mountainous terrain provides for
multiplication of niche space.28-30
3.6.3. Behavioral Benefit. Horses and burros aid myriad
plant and animal species by their physical actions. As an
example, breaking of ice with their hooves during winter
freezes allows other animals to access forage and water.
Many of these would otherwise perish. Similarly, they open
trails in heavy snow or through heavy brush, allowing
smaller animals to move about in search of food, water,
mineral salts, shelter, warmer areas, mates, etc. A little
recognized fact is that the wallowing habit of wild equids
creates natural ponds whose impacted surfaces become
catchments for scant precipitation or summer cloudbursts
typical in the Great Basin. These provide a longer lasting
source of water for a wide diversity of plants and animals.
This can even help to create an intermittent riparian habitat
for desert amphibians (e.g., the remarkable spadefoot toad,
which seals itself into a dry, muddy cocoon for many years,
reanimating when moisture is again present) and many
other desert species.31 Ephemeral plants that quickly flower
and set seed, including many composites, are benefited
from these catchments – especially valuable in regions with
clayey soils. Wild equids also locate water seeps through
their keen sense of smell and enlarge these through pawing
during critical dry periods of the year, even digging down
to the sources at rocky fissures. This allows many other
species to access water, species whose individual members
would otherwise perish. For these and many other reasons,
wild horses and burros should be treated as keystone
species that contribute positively in a variety of ecological
settings. Indeed, these and other equid species have been
keystone species in North America for many millions of
3.6.4. Role as Prey. Wild horses and burros are natural
prey of native carnivores and omnivores, including puma,
wolves, and brown and, to a lesser degree, black bears. In
geologically recent times, this included the famous saber-
toothed tiger and dire wolf. Unfortunately, these natural
hunters have been targeted for elimination by humans. This
has severely reduced the natural predators of deer, elk,
moose, pronghorn, bison, bighorn sheep, and other prey
species upon which these native predators have subsisted
for thousands of generations and in a way that makes the
prey populations more fit to survive over the long-term by
taking the weak, infirm or those animals reaching the end
of their life cycle.32 The “trophic cascades” that natural
predators cause in an ecosystem lead to the greater
biodiversity and stability of such.
With practically no break unto relatively present times,
equid species have filled the ecological role of medium-
and large-sized prey mammals in North America for over
58 million years. Today, the wild horse and burro are
refilling their empty niches that have been only briefly
unoccupied, paleontologically speaking, if at all. These
niches are the product of countless generations of
coevolution with native plants and animals. Today, it is
highly questionable how individual western states such as
Idaho, Montana, Utah, and Wyoming are allowing open
season upon wolves, yet the officials of these same states
will dishonestly claim that wild horses and burros have no
natural predators.
3.6.5. Coevolution with Habitat. To quote Dr. Jay
Kirkpatrick and Dr. Patricia M. Fazio[5]: “[t]he Key
element in describing an animal as a native species is: (1)
where it originated; and (2) whether or not it coevolved
with its habitat. Clearly, E. caballus did both, here in North
America.” Various Amerindian tribes of the Great Plains
and Prairies have a saying concerning the wild horses: ‘The
grass remembers them.’[15] (See also Downer[34].)
Wild horses and burros are perfectly suited to life in the
remote, semi-arid regions of the West. One reason is
obvious: their great mobility. With their long limbs and
sturdy, single-unit (soliped) hooves, they are made for
movement. In such semi-arid or arid regions as they
inhabit, this extensive movement is vital for survival. In
order to obtain enough forage, a wild horse must often
roam over several square miles each day, selecting
appropriate plants to prune; reaching a water hole may
involve traveling over one hundred miles round trip in a
grazing circuit of two or three days.
During very hot, dry spells, a wild horse band must stay
close to water, tanking up every day with approximately ten
to twelve gallons for a mature horse. A spring can be shared
by several bands. These form an orderly hierarchy for
watering should more than one band arrive at a source at
the same time, often late in the day. When melting snow or
fresh cloudbursts paint the land with ephemeral water
sources, wild horses can disperse into areas further away
from perennial lakes and streams and to ephemeral sources.
Here they employ their keen sense of smell in detecting
even very small and hidden water sources. They can also
negotiate rougher, steeper and rockier terrain than domestic
Through a hammer-like hoof action upon the ground,
wild horses and burros aid vegetation by pushing seeds
firmly into the soil where they may successfully germinate.
In October 2008 at the Wild Horse Summit in Las Vegas,
Lakotan Sioux shaman Arvole Looking Horse of South
Dakota described to me how wild horses are vital
energizers that “pound Earth's drum” releasing energy from
the inner planet and lending a musical rhythm that unifies
diverse forms of life. Though criticized by their detractors
for breaking the crusts, or desert pavement, of certain
desert soils and, thus, accelerating wind erosion, when
allowed adequate space and freedom, horses do not
overwhelm an area. This is due to their sparse distribution
and frequent movements and because, as most land-bound
animals, they confine the majority of their long-distance
displacements to trails. In certain areas, their compacting of
soils helps these retain scant precipitation and dew.
Especially in soils of higher clay content, this compaction
can help retain moisture over long periods of time.
However, such modification of soils, occurring naturally
with nearly any hoofed animal, can become detrimental to
an ecosystem with overcrowding. As with any activity,
what is an ecological positive in moderation can become a
serious problem when overdone. This is certainly the case
with the severe overgrazing that humanity has imposed
upon the West, as upon similar arid and semi-arid regions
throughout the world. This they have done by forcing
hordes of cattle, sheep, goats, deer, yaks, and, yes, even
horses or burros, etc., in unnaturally high concentrations
upon the land. The problem is with the people, not the
3.6.6. Man’s Impact. In the latter 1800s, many millions
of cattle and sheep were forced by their human possessors
into the vast, unfenced western regions. While a graduate
student at the University of Nevada-Reno, I viewed
archival photographs from the late 1800s of interior regions
of Nevada such as the Reese River or Humboldt River
hydrographic basins. These revealed extensive valleys
filled with exuberant tussock grasses that were soon to be
replaced by unpalatable sage and rabbit brush due to
livestock overgrazing, as more recent photos in the same
places conclusively prove. In effect, we humans raped the
West, greatly setting back this formerly healthy, though dry,
life community.37 We ignored the already established life
communities that in many places included the returned
native–or perhaps aboriginal--mustangs, and the possibility
of harmonizing with such, while ignorantly imposing
domesticated European species with a mind to maximizing
production and profit in the short term. Today the arid
terrestrial ecosystems our culture so invaded continue to be
grazed by domestic livestock, though controls were
imposed in the U.S. starting with the passage of the Taylor
Grazing Act of 1934. Though somewhat alleviating the
situation, this act assured that these lands would still be
monopolized by livestock interests, thus, preventing the
type of recovery that should and still can occur.38
3.6.7. Dust, Gas and Effects of Livestock & Global
Warming … Place of Wild Horses. Among the most
insidious and globally harmful effects of domestic livestock
hordes are the large quantities of dust blown into the air
when the surface of soils are overly trampled and grazed.
An article in Nature has revealed that “dust load levels
have increased by 500% above the late Holocene [eleven
thousand years ago] average following the increased
western settlement of the United States during the
nineteenth century.” This is largely attributed to “… the
expansion of livestock grazing in the early twentieth
century.”39 The dust causes an increase in various chemicals
affecting the pH of water, productivity, and nutrient cycles.
Such fine particles can settle on plants and plug their tiny
pores, or stomata, through which they breathe. They can
also lodge in the interstitial lung tissues of many animals,
including humans, where they cause pulmonary diseases,
including cancer. Though insufficiently recognized, the
“dusty factor” is extremely damaging both to living
organisms and the ecosystems they inhabit.
The enormous quantities of methane, nitrous oxides, and
other gases that are emitted through the digestive processes
of domestic livestock constitute one of the major
accelerators of life-threatening global climate change.40
Clearly, civilized man’s so-called progress upon planet
Earth has abysmally failed to consider the ecological
balances that assure life’s continuance. Urgently required is
an all-out effort to restore the natural diversity of plant and
animal species appropriate to each of the Earth’s bio-
regions, or ecological provinces, as to the Earth as a whole.
But this is going to involve a serious willingness on the part
of us humans to modify our life-influencing values and
priorities, both individually and collectively. This will
permit us to live in a truly harmonious manner, to act as
good neighbors toward our fellow species. Here the horses
and burros come into play. Their post-gastric digestive
system does not emit as much gas as is the case with pre-
gastric ruminant grazers, and permits them to greatly
reduce dry, fire-prone vegetation over vast areas of the
West without overtaxing their metabolism. Thus, they help
to prevent catastrophic fires that global warming, or more
to the point, human civilization’s pollution of the
atmosphere is causing.
By drying out vegetation and provoking catastrophic
fires rampant in western and southern North America,
Australia, and much of the world the catchall global
climate change threatens planetary life as we know it. This
will especially be the case if global ocean currents stop
circulating due to glacial and ice cap melting, etc. Annually
a few to several million acres of forest, brush, and
grassland have been going up in smoke in the United States
alone, especially in the West and South. Never in historic
times have we seen such destruction. But wild
horses/burros can greatly help to save the day if allowed to
play their own special role in reducing flammable
vegetation, in building soils, in seed dispersal, in
preventing catastrophic, soil-sterilizing fires, etc. They
stand ready to counter imbalances brought on by human
civilization and its contamination of the atmosphere. Much
of this contamination is caused by hordes of domestic
livestock that mow down vast vegetated areas, their over
concentration and resultant destruction of soils, and their
production of flatulence and excrement in enormous
proportions and intensities. Of course, there are also
imbalances brought on by automobile exhaust, factory
fumes, forest burning, peat oxidation in the Subarctic and
Arctic, absorption of sunlight by darker seawater where
once reflective ice caps stood and of sunlight by dark soot
deposited on glaciers, etc. Millions of years of coevolution
have made equids best equipped to prevent the catastrophic
fires we are experiencing and to restore many of the
ecosystems human civilization has either blindly or
intentionally damaged. Let us not take these magnificent
animals and what they have to offer for granted, for they
are definitely a key part of the solution to all life’s
problems today.41
3.6.8. Cheat Grass and Further Ruminations. A
commonly eaten food of wild horses in northern Nevada’s
Granite Range is Bromus tectorum, a.k.a. the infamous
“cheat grass” that is taking over the West.[42,38] The
measured percentage frequency of this invasive species
from Central Asia in the Granite Range habitat was 89.9%,
while the percentage cover was 12% and the percentage use
by wild horses was a full 27.3%.[38] Since cheat grass is a
major contributor to fires in the West, perhaps wild horses
as well as burros could be a major agent for reducing this
flammable vegetation. Equids could prevent its
reproduction by consuming this grass before it is able to set
seed, in spring or early summer, depending on elevation.
Most of the other species in Dr. Berger’s table also become
dry and flammable and are eaten by horses, thus reducing
the “fire fuel load” in their occupied habitat. Wild horses
and burros, as well as zebras, are very effective fire hazard
reducers. They are more effective in eliminating cheat grass
and other dry, flammable grasses and forbs than many
ruminant grazers, and spread their grazing over larger
areas, provided fences and other barriers do not overly
confine them. They eat during 60% to 80% of the 24-hour
day (ca. 15 hours), keeping constantly on the move and not
camping on moist riparian or lacustrine meadow habitats,
as do domesticated cattle put out to graze on the same land.
Their droppings also build the humus content of soil to a
substantial degree. This humus allows soil to gain more
texture and retain more water, which dampens out fires;
humus promotes more productive and bio-diverse plant and
animal communities.43 Because their feces are not as
thoroughly degraded in the gut as those of ruminant
grazers, they contribute more to food chains/webs, e.g.,
dung beetles to birds and lizards to higher trophic predators
such as bobcats and eagles, etc. Equine feces aid the
watershed by creating damper conditions, because the soil
particles to which they reduce (micelles) retain more
moisture, i.e., more water adheres to the surface area of
these particles. Hence, ground water tables are replenished,
feeding more seeps and springs more continuously. And
upon these springs and seeps, many species of plants and
animals depend. Of course, some fire is of benefit to an
ecosystem, but fires that over-consume, over-extend, and
over-intensify can set the evolution of a terrestrial life
community way back and result in a very sterile
environment that could take thousands of years of “peace”
to recover.
3.6.9. Upper Incisors and Further Insights. Insight can
stem from the most basic of observations. For example,
wild horses and burros possess both upper and lower
incisors that permit them to selectively nip pieces of
vegetation, such as grass or the leaves of bushes or trees.
Major ruminant grazers, as for example cattle and sheep, do
not have upper incisors and consequently can and do rip up
plants by their roots more frequently with the action of their
lower teeth and tongue against their hard upper palates.
This often exposes soils to destructive wind and rain
erosion, especially when too many of the ruminants are
placed upon any given area of land.
When over-crowded upon dry rangelands or marginal
western brush or forest lands, livestock have and continue
to cause enormous ecological degradation. Yet, the problem
lies not so much with the animals themselves but with the
humans who force them into habitats where they did not
evolve and, more to the point, where they are not even
allowed to harmoniously evolve and adapt to prevailing
conditions through the time-honored process of natural
selection and ecological balancing.[36] About three-fourths
of the U.S. public lands are in seriously degraded condition
due to overgrazing by domesticated livestock. The root of
the problem lies not with the animals themselves but with
we people who unnaturally manipulate and force them
upon the land.
3.6.10. Mutualist Equids Helping to Provide Ecological
Stability. Though domesticated for a relatively short
evolutionary time, horses and burros actually restore the
wild “equid element” in North America. Here they refill
herbivore niches that have been millions of years in the
making. This restored diversification lends greater stability
and balance to the ecosystem by increasing the complexity
of the web of life. This interdependence involving equids
has been documented in the Serengeti of Africa by Bell.27
Bell observed how zebras eat coarser, drier grasses, etc., to
expose to sunlight (allowing greater photosynthesis) finer,
more delicate grasses, forbs, and other types of mature
plants or their seedlings, thus, permitting their growth. The
latter are more appropriate forage for wildebeest,
Thomson's gazelle, topi, etc., that come in later seasons. A
migratory sequencing of grazing pressures by these
different species evolved over thousands of generations,
and this is mutually beneficial to these species.
A similar complementarity to that of the Serengeti
evolved in North America and involves members of the
horse family, including Equus caballus. As earlier
explained, the latter originated and evolved upon this
continent during the past few million years, as did its
preceding ancestry dating clear back to the Dawn Horse,
Hyracotherium, a.k.a. Eohippus, of at least 55-million-year
antiquity. The plains and prairies of North America were
home to a dynamically balanced community of prairie
dogs, bison, rabbits, pronghorn, deer, wolves, bear, foxes,
coyotes, puma, diverse rodents, reptiles, and amphibians,
raptor and song birds, snails and myriad insects and
spiders, recycling microorganisms, etc. Over the many
generations of their coevolution and in their complex
feeding, decomposing, photosynthesizing, pollinating, seed
dispersing, warning, and other interactions, these have
fashioned a life community that is highly adaptable to the
vagaries of climate, volcanic activity, unexpected
oscillations in the sun's radiation, etc. In other words, the
complex web of species – as any true web – has provided a
beautiful resilience involving cyclings up and down for all
species. With this greater variety of species, the natural
vagaries that pose ever new and different survival
challenges can be ridden out by the whole of life. In this
respect, any individual, family, race, or species of life is
like a rider of a bucking bronco, entered into the greater
arena of evolving time and circumstance, in a rodeo whose
rules are set according to natural and universal law.
Understanding this allows us to understand the changing
proportions of species present in North America over time
as a response to changing conditions, both living and so-
called non-living.[1]
A salient example of harmonious coexistence occurs
between deer, either white-tailed or mule, and wild horses.
Deer mainly browse the leaves of trees or bushes while
horses eat mainly grasses when available. In a healthy
habitat, these deer and horses hardly compete because of
utilizing different resources, and their interactions are often
of mutual benefit. These benefits may be obvious or more
subtle, direct or indirect. A similar harmony exists between
mustangs and pronghorn an ancient and singular species
that originated in North America, as did the horse.[44] The
latter two have had a long time to learn to get along.
Incidentally, the pronghorn seems never to have left North
Wild horses particularly thrive in North America's plains
and prairies, but can adapt well further west of the Rockies
in the Great Basin and west of the Sierra Nevada mountains
in California, as they did so well in earlier centuries. Burros
adapt well in drier areas of North America particularly in
the arid Southwest. Both equid species diversify and
strengthen the community they inhabit in a variety of ways
when allowed to achieve population stability over time and
when not over-imposed upon by humanity. The process of
natural selection must be allowed to operate sufficiently
long for this to be the case. Then these equids create a
greater variety of environmental conditions that make
possible a greater variety of niches that can be occupied by
the species that have coevolved with them and continue to
evolve here on planet Earth. Begin large, powerful animals,
equids can push their way through thickets of brush to form
trails. Specifically, they open thick vegetative understories
to light and air, and the more diverse exposures resulting
from equine activities create conditions intermediary to the
extremes of wind, temperature, and various soil conditions.
This physically defines a greater variety of niches fillable
by a more diverse array of species.
When allowed to integrate into wilderness, the individual
life histories of wild equids come to reflect natural
oscillations, such as annual seasons and more long-term
cycles. This they do along with the plants and animals who
share their habitat. They harmoniously blend over time. As
large animals who eat relatively large quantities and
disperse their grazing and browsing activity over broad
areas as semi-nomads, equids become the harvesters and
the renewers over vast ecosystems, true to their keystone
role. Their cropping of vegetation, often dry and coarse,
reduces the possibility for major, soil-sterilizing fires
(though ecologically healthy, minor ones still occur). This
cropping sparks vegetative renewal, the re-budding of new
and tender shoots of greater nutritional value, especially to
ruminants whose digestive and metabolic systems are over-
taxed by the coarse, dry vegetation that horses and burros
can better handle. And, thus, the overall productivity of the
land is annually increased.[45, 46] Also, as earlier noted,
these equids disperse the seeds for successful germination
of many of the plants they eat as well as fertilize the soils
with their droppings. For their neighbors including the
ruminant grazers, their presence is truly “win-win.” And
this I have also observed to be the case with the threatened
Greater Sage Grouse in places such as eastern Nevada’s
Triple B Complex of HMAs. Here these impressive lek-
forming birds thrive alongside the spirited mustang bands.
3.6.11. Rewilding. It is sometimes asserted that horses
have not been part of the North American life community
since their die-out at the end of the Pleistocene epoch, i.e.,
the last ice age (Larry Johnson, BLM National Wild Horse
and Burro Advisory Board, pers. comm.). Even if they did
die out (which seems untrue), and though (based on the
fossil record) a great subsidence in their numbers did occur
for a relatively brief time period of ca. 7,000-10,000 years,
such a time period is not sufficient to undo the many
mutualistic relationships horses established with native
plants and animals.[5] Furthermore, it is widely recognized
that North America became species poor, or depauperate, in
large mammals after the massive Pleistocene extinction that
affected many other mammals, e.g., giant ground sloths,
camels, rhinoceroses, saber-toothed tigers, dire wolves,
tapirs, mammoths, and mastodons. In light of the foregoing,
the return of the horse and the burro can be viewed as a
restoration of the North American ecosystem, a resuming of
an age-old continuum, a repair in the anciently evolved web
of life – in other words, a “rewilding.”[47-49]
It is of vital importance that this rewilding take place
today given the melting of the permafrost and so as to
restore cool grasslands over extensive regions, including in
Siberia.[50] Horses undoubtedly played a crucial role in
building rich soils and in dispersing the seeds of many plant
species composing the Pleistocene savannas of North
America and should be greatly valued as returned natives
here.[47] Along with the burros, they are a different type of
herbivore, possessing a post-gastric digestion, as contrasted
with the ruminant digestion typical of the other major
North American herbivores today.
3.6.12. Identifying the Problem and Its Solution Us!
Livestock currently graze western public lands in the
equivalent of over a million year-round cattle, and big
game interests promote unnaturally numerous deer herds
for hunter harvest. Both ranchers and hunters seek to
eradicate native predators, such as pumas, wolves, and
bears. Combined with other pressures such as subdivisions,
off-road vehicles, mining, and energy development, this has
created an unbalanced situation in which ecological
recovery is not possible. On top of this, global climate
change is exacerbating the situation. The solution to our
predicament lies, above all, in our becoming more sensitive
toward and more knowledgeable about the ecosystems we
inhabit and the more optimal potentials that both people
and ecosystems can realize in unison.
3.7. History of Wild Horse and Burro Program and
Public Lands in U.S.
3.7.1. Germane Facts and Figures. In spite of the
mandate of the Wild Free-Roaming Horses and Burros Act
of 1971, over 27 million of the admitted 53.5 million Herd
Area (HA) acres have been “zeroed out” by the BLM and
USFS in order to establish 26.5 million acres of Herd
Management Areas (HMAs).[51] After reducing the
original ca. 350 HAs to 180 HMAs on BLM land,
Appropriate Management Levels (AMLs) have been
developed that are in most cases non-viable in each given
HMA. Most of these levels do not even meet the
requirements for Minimum Viable Population of 150
horses/burros per herd commonly recognized by the BLM
and fall far short of the 2,500 individuals recommended for
a viable population by the Equid Specialist Group of the
IUCN Species Survival Commission.[52]
Of the 180 greatly-reduced HMAs throughout the West,
130, or 72%, have AMLs of less than 150, and many of
these are much less than 100, even numbering in the teens.
According to the BLM’s own standard of 150, in California
19 out of 22 HMAs have non-viable AMLs; in Utah, 17 out
of 21; in Idaho, 5 out of 6; in Montana, 1 out of 1 (6 of the
original 7 HAs having been zeroed out); and in Nevada, 67
out of 90 of the remaining herds are similarly non-viable.
The Congressional Research Service reports that, in
FY2005, forage eaten on BLM lands by livestock summed
up to 6,835,458 Animal Unit Months (AUMs), contrasting
with wild equid consumption of only 381,120 AUMs, or
5.6% that of livestock. On USFS lands, livestock devoured
6.6 million AUMs worth of forage, much of this in vital
headwaters, while wild horses and burros got by on a
meager 32,592 AUMs, or 0.5%.[54] These figures suggest
that cattle, not equids, may be responsible for overgrazing,
erosion, threats to native species, and other ecological
problems seen in the arid West
3.7.2. More Whittling Away, Some Needed Perspective.
BLM reduced the forage allocations, or animal unit months
(AUMs), for wild equids by 17% between 2002 and 2005,
citing drought conditions and ignoring: (a) wild equids' pre-
adaptation to consume large quantities of dry flammable
vegetation (a larger portion of which has resulted from
global climate change) and, so, to reduce catastrophic fires,
(b) their role in combating global climate change over the
Earth's vast steppe or steppe-like biomes by preserving
permafrost and/or establishing tundra grassland where
permafrost has melted,[50] and (c) the fact that wild equids
are capable of grazing much steeper and more rugged areas
further away from water than cattle, which tend to
concentrate their activities around water sources.
Cattle and sheep grazing on U.S. Public lands contribute
substantially to global climate change through their release
of enormous quantities of methane gas and nitrogen oxides
involved in ruminant digestion and through the widespread
degradation of ecosystems, especially riparian.[40,55] Yet,
the reduction for livestock in drought-stricken areas has
been only 4% even though they greatly outnumber the wild
equids that have been reduced by 17% and as of January
2014 about the double of this.
Permittees only pay a small percentage of fair market
value, at present amounting to about 9% to 12%, in order to
graze their livestock on the public lands. This was
reauthorized (March 2011) and remains (January 2014) at
the minimum required by the Taylor Grazing Act of 1934:
$1.35 dollars per AUM, a measurement that includes a cow
and her calf (that have grown much larger due to genetic
manipulation and selective breeding over the ensuing years
since 1934). The Government Accounting Office[56]
reported that the government lost at least $123 million in
order to prop up public lands livestock grazing, while real
costs have been estimated as at least one-half billion dollars
per year when ecological damages are added in (Center for
Biological Diversity[57]). To put the situation in
perspective, there are nearly 22,000 public lands ranchers
in 13 western states, about one for each wild horse or burro
allowed in the nationwide Appropriate Management Level.
Further, the top 10% of the ranchers – often large
corporations, wealthy bankers, lawyers and doctors own
over 65% of the livestock grazing in public lands.
Similarly, the cattle/sheep culture has played a major role
in destroying indigenous Andean wildlife, especially the
endangered mountain tapir, now reduced to only a few
thousand individuals.[28, 29, 30] Enormous ecological
damage has been done throughout the Americas, especially
since the arrival of Europeans, but also before by some
groups of Amerindians, although not to nearly the degree.
In the U.S. west of the Mississippi River, ca. 700 million
acres of grassland have been degraded due to overgrazing
by uncontrolled millions of cattle and sheep; yet left to their
own devices, these animals would either harmoniously
adapt or perish. In 1884, the region of today’s western
states held ca. 40 million cattle in addition to millions of
sheep. It was not until 1934 that this cancerous destruction
was in any way checked through the Taylor Grazing Act –
yet, unfortunately this act perpetuated the control of our
public lands by private livestock interests.
4. Conclusions and Recommendations
Wild horses form tight-knit stallion- and elder-mare-
governed bands. Over time, each band searches out and
establishes its own home range, which may cover hundreds
of square miles on an annual basis in drier regions. The
ecological mosaic that results among all such particular
band home ranges in a given Herd Area/Territory and
suitable adjoining areas prevents overcrowding and
overgrazing. Once available habitat is filled, the
horse/burro, as a climax species, limits its own population
as density-dependent controls are triggered.
In the immediate future, true wild horse- and burro-
containing nature sanctuaries need to be established. Here
livestock should be excluded or at least greatly minimized
and wild horses or burros allowed to establish viable
populations in the thousands, not mere hundreds or less
than one hundred as currently proposed. These fairly
populated sanctuaries will be viable in the long-term. They
will preserve the vigor of the horses and burros they were
designed to conserve.
4.1. Reserve Design
4.1.1 Basics of Reserve Design. To address these
problems, I present a workable solution. This will be to
restore wild equids in their legal Herd Areas and Territories
as outlined in the Wild Free-Roaming Horses and Burros
Act of 1971, and, hopefully, in all ecosystems where they
play a crucial role. Let us plan a modus operandi by which
to reestablish wild equid herds at long-term-viable
population sizes within long-term-viable habitats, adequate
in all respects as to size, water provision, food availability,
shelter, mineral requirements, and elevational gradients.
The latter will allow for seasonal migrations to higher areas
during the summer and to lower areas during the winter. In
these areas, wild equids will be treated as the “principal”
presences, as the Wild Free-Roaming Horse and Burro Act
of 1971 intended; they will no longer be given secondary or
even last priority by the very authorities whose duty is to
uphold – not subvert – the federal laws protecting them.
Employing principles of Reserve Design,59-61 the
following directives will serve to guide us:
(a) Let wild horses/burros reoccupy their full legal Herd
Areas wherever possible and in no case less than 75% of
the original legal area. And where a reduction in equid
occupation of the original Herd Areas/Territories is deemed
necessary, there must be a compensatory acquisition of wild
equid habitat of equal or greater value as judged by
independent wildlife ecologists with particular knowledge
of wild horse and burro requirements. To accomplish this
reoccupation, authorities should employ Codes of Federal
Regulations 4710.5 and 4710.6 to reduce or curtail
livestock grazing within legal Herd Areas and Territories.
Also, they should authorize the purchase of grazing
permits, base properties, and water rights that are
conflicting with the sound establishment of the legal wild
horse and burro herds. All Implied Federal Water Rights
that come with the legal Herd Areas or Territories will be
protected. Sections 4 and 6 of the WFHBA will also be
exercised in order to secure complete, viable, long-term
habitats for long-term viable wild horse and burro
populations, as is the true intent of the Wild Free-Roaming
Horses and Burros Act of 1971.
(b) Employ natural barriers or, where such do not exist,
semi-permeable, artificial barriers, where possible and
necessary, in designing each wild horse/burro Herd
Area/Territory as the true sanctuary the law intends. These
barriers will act as limits, or impassable boundaries, to wild
equid expansion. These will contain each wild equid
population within its legal domain, as legally expanded
where necessary to provide long-term-viable habitat and to
keep wild horses/burros out of harm's way, i.e., out of areas
where they would be in clear and unavoidable conflict with
human activities. Here I particularly recommend the
employment of special Strieter-Lite light reflectors that
prevent nighttime collisions of animals with automobiles
wherever major roads or highways transect the wild equid
Herd Areas/Territories. Also, intelligent use of drift fences
can serve to effectively contain horses at strategic passes,
etc. But none of the foregoing shall be used to restrict the
wild horses/burros within their large, viably sized and
complete habitats, as shall be knowledgeably and
sensitively defined well in advance.
(c) Design and employ buffer zones around the wild
horse Herd Areas/Territories. Here a gradual tapering off of
wild horse or burro presence would occur through the
implementation of discouragements to their transiting into
areas where danger exists for them, such as in farms or
cities. This may involve the use of what wildlife managers
term “adverse conditioning” that need not be overly harsh
to be effective. The effectiveness of buffer zones depends
to a high degree on public education, on working
agreements with the people who live in or around each
Herd Area/Territory. These agreements will foment win-
win relationships for both wild equids and people. Locals
would monitor and protect the herds and their habitats and
derive benefit for doing this as well as from eco-tours, and
would be encouraged not to feed the equids. These buffer
zones would be established according to principles of
Reserve Design and in a positive manner respecting the
wild equids.
(d) Allow each wild horse/burro herd to fully fill its
ecological niche space within each given legal Herd
Area/Territory bounded by natural or where necessary
artificial barriers, and by buffer zones. Then allow each
specific herd to self-stabilize, or auto-regulate, its
population, within this area. Such auto-regulation can
happen if we humans allow. Both horses and burros are
“climax species,” which is to say, members of the “climax
successional sere,” or stage, and do not expand out of
control to destroy their habitat and ultimately themselves.
In other words, each band within a herd population is
usually governed by a lead stallion (patron). He watches
out for and defends the band and does most of the breeding.
A usually older, lead mare also aids in this role. This mare
is very wise as to where the best foraging, watering,
mineral procurement, sheltering areas, etc., are located. She
leads the band along paths uniting these habitat
components. These include longer seasonal migratory
routes between higher summering and lower wintering
habitats. Both patron and lead mare socially inhibit
reproduction among younger members of their band.
Each band establishes a home range within and/or
outside the legal Herd Area/Territory, according to its
survival necessities. And all of the bands taken together
form a mosaic of somewhat overlapping but generally
distinct home ranges. Given enough time to work out their
individual and collective differences, wild horses reach a
more stable state in relation to their bounded habitat. They
do not overpopulate and destroy this habitat but rather auto-
limit, achieving a balance with the natural resources of their
Herd Area/Territory.
Of crucial importance here is the optimal size of habitat
that should be made available to each wild equid herd in
order to provide for an optimally viable population. This
will depend upon the productivity and carrying capacity of
the land. To be minimally viable and considering today’s
political constraints, I recommend that each herd contain at
least 500 and to be optimally viable for long-term survival
over the generations, each herd should be well over 1,000
interbreeding individual animals and this should be the
long-term goal. Remember that the IUCN SSC Equid
Specialist Group recommended a minimum size of 2,500
individuals per herd in order to achieve long-term viability
for a wild equid population, and a minimum size of 500 for
a carefully managed domesticated population.[52] Again,
equids possess means of limiting their own reproductive
capacities, either socially or biologically, when resources,
including food, water, and space, become limiting. This
involves stress and hormonal factors.62
(e) In order to realize healthy, balanced wild horse/burro-
containing ecosystems in each of the Herd
Areas/Territories, as full a complement of plant and animal
species, each filling its specific place and role, should be
allowed. Wherever possible, this should include large
carnivores/omnivores native to the region in question, such
as puma, wolf, and black or brown bears. These will
provide a natural control on the equid population,63 one that
will act through natural selection to make any given
population more fit, or “toned”, for survival in the wild and
more adapted to its particular ecosystem. And the refuge
should also include as large a variety of other large,
medium, and small herbivorous, carnivorous, and
omnivorous species as possible: rabbits, mice, prairie dogs,
foxes, coyotes, deer, pronghorn, beaver, skunks, weasels,
raptor birds such as hawks and eagles, scavenger birds such
as vultures, song birds, and myriad lizards, snakes, rodents,
amphibians, mollusks, and insect species. This animal
complex will, of necessity, be based upon a similarly
diverse collection of plant species, including a complex
mixture of grasses, herbs, shrubs, and trees, tending as
much as possible to the autochthonous, or native, and
supportive of a complete series of inter-complementary
animal pollinators, seed dispersers, decomposers, species
related as predator-prey, etc. Thus, the safeguard of greater
biodiversity in the web of life will be allowed to make a
comeback and be further enhanced.
4.1.2. Reproductive Inhibitors and Reserve Design. In
March 2008, BLM officials were considering castrating
wild stallions in their legal Herd Areas to prevent their
reproduction. I pointed out that, in addition to being cruel,
this could precipitate inbreeding, because fewer stallions
would actually fertilize the mares. Since horses naturally
form harems, the dominant stallion of each does the
majority of the breeding; although a certain percentage of
the breeding may be done by subdominant stallions.42
Given castration, the male contributors to the gene pool
would be greatly reduced and the specter of inbreeding
would loom, as survival prospects for any given population
would grow dimmer. Also, castration has caused stallions to
be socially ostracized, attacked by kicking, and generally
marginalized from the wild horse social groups in which
they would otherwise be accepted (pers. obs.).
BLM plans to use “aggressive birth control” to prevent
the expansion of the wild horse/burro populations that
remain. Chief among the drugs to be used is PZP (porcine
zona pellucida). This injected drug covers the eggs, or ova,
of mares, preventing sperm from fertilizing them. It is
experimental, however, and has some very questionable
effects upon the horses themselves, both individually and
collectively. For example, its effect leads to mares’
repeatedly recycling into estrous, thus stimulating stallions
to repeatedly mount the treated mares – all to no avail. This
frustrating situation causes much stress among individuals
of both sexes and a general disruption of the social order,
both within bands and, as a consequence, within the herds
Other unintended consequences of PZP are out-of-season
births occurring after PZP’s effect has worn off after a year
or two. These births have been observed during the colder
late autumn and winter seasons (e.g., Pryor Mountain herd
by G. Kathrens of The Cloud Foundation); and their
untimeliness causes suffering and death among both foals
and their mothers. The current experimental use of PZP
delays the fertility of thousands of mares dispersed
throughout many wild horse herds. It is another way BLM
is “taking the wild out of wild horses.” Along with the very
low Appropriate Management Levels BLM has established,
this is proving yet another tool for “management for
extinction.” Both out-of-season births and accelerated,
unfruitful estrus cycling undermine wild horses’ ability to
survive in the harsh climate of the Pryor Mountains and
similar places throughout the West, by causing social
instability both within and among the bands, etc. Long-time
roundup contractor, Dave Cattoor confirms some of
Kathrens’ alarming observations, particularly out-of-season
births and the excess stress on mares and the stallions that
repeatedly try to impregnate the mares in vain.
The injection of GnRH is a hormonal way of preventing
reproduction in mares, but is observed to produce serious
suffering and aberrations, just as it does with women, in
whom it has also been linked to cancer. It is also being
considered for use with the wild equids. Another inhumane
way involves extraction of ovaries, which has been
experimentally employed on the Sheldon NWR’s wild
horses, among which it has caused terrible suffering and
The answer to the wild horse crisis is not to be found in
manipulations that are contrary to the caring spirit and
wisdom of the WFHBA and its “minimal feasible level” of
management tenet (Section 3a). Rather, the solution is to be
found in proper wild land Reserve Design. As detailed
above, such involves natural and/or artificial, semi-
permeable barriers, natural predators, as well as
community-involving buffer zones, among other tools,
including allowing the horses/burros to naturally fill their
niche in any given area. Future wild horse/burro reserves
will contain complete habitats, large enough to support
long-term-viable wild horse/burro populations.
4.1.3. Regions for Reserve Design (See Figure 4, map).
Some of the major regions where Reserve Design should be
implemented are:
(1) Southeast Oregon, including Steens Mountain and
Alvord Desert with its Kiger mustangs.
(2) Northwest Nevada with its Calico Complex and High
Rock Complex of wild horse and burro Herd Areas.
(3) Northeast California including Twin Peaks,
Coppersmith, New Ravendale, and Buckhorn Herd
(4) Northern Nevada and the Owyhee Desert complex of
wild horse Herd Areas.
(5) North Central Nevada including the Clan Alpine wild
horse Herd Area and adjacent Herd Areas such as the
Desatoya, New Pass, and Mount Airy.
(6) Eastern Nevada including the Triple B Complex of
wild horse Herd Areas and Territories.
(7) Southeastern Nevada including the Caliente Complex
of wild horse and burro Herd Areas.
(8) Southwest Nevada and adjacent parts of Eastern
California including Montgomery Pass wild horse
Territory, Monte Cristo and Silver Peaks wild horse
Herd Areas, and Marietta Wild Burro Range (BLM).
(9) Central Southern Nevada centered on the National
Wild Horse Range (Nellis Air Force Base).
(10) Panamint-Centennial-Slate Range Wild Burro Herd
Areas complex, Southeastern California.
(11) Southeast California wild burro Herd Areas, including
Clark Mountain.
(12) Southern California wild horse and burro Herd Areas
including Coyote Canyon.
(13) Southern Nevada wild horse and burro Herd
Areas/Territory including Spring Mountain.
(14) Western Arizona wild burro and wild horse Herd
Areas including Lake Mead burros and Cibola-Trigo
and Cerbat wild horse herds.
(15) Southwestern corner of Arizona and adjacent areas of
Southeastern California for wild burros.
(16) Southwestern Utah bordering on Nevada including
Sulphur wild horse herd.
(17) Western Utah wild horse Herd Area south of Great
Salt Lake and the town of Tooele.
(18) Southern Wyoming complex of wild horse Herd
Areas, including Adobe Town-Salt Wells Creek
Complex and White Mountain and Red Desert herds.
(19) North Central Wyoming and Southern Montana
including Pryor Mountain Wild Horse Sanctuary and
McCullough Peak wild horse Herd Area on NPS land.
(20) Northwestern Colorado including Sand Wash Basin
wild horse Herd Areas, including West and East
Douglas wild horse Herd Areas.
(21) New Mexico wild horse and burro Herd
Areas/Territories, including Jicarillo, Bordo
Atrevesado, and Carracas Mesa herds.
(22) Central Idaho wild horse Herd Areas/Territories.
(23) Restored Montana wild horse Herd Areas/Territories
in the southwestern part of this state.
The above and additional important regions should be
carefully examined as concerns the major requirements of
Reserve Design with a mind to its practical
implementation. This should happen immediately in order
to prevent the further demise of America’s last wild horse
and burro herds. This program would seek to restore the
herds to naturally (ecologically) integrated and truly viable
population levels. In conjunction with this, other private
and public lands would become involved, as is consistent
with Sections 4 and 6 of the Wild Free-Roaming Horses
and Burros Act of 1971, among other legal mandates, e.g.,
the Multiple Use and Sustainability Act, the National
Historical Preservation Act, the Endangered Species Act,
and the National Environmental Policy Act. Wild equid
herds occurring in other states not on BLM and USFS
lands, such as the Lakota wild horse-occupied areas in the
Theodore Roosevelt National Park, would also be included
in this program.
Remnant lineages of wild horses and burros that are
being maintained on private sanctuaries would be called
upon to restore zeroed-out Herd Areas/Territories wherever
possible. These would include the Wild Horse Sanctuary
near Shingletown, California, the Return to Freedom
Sanctuary near Lompoc, California, the ISPMB wild horse
sanctuary near Lantry, South Dakota (preserving the White
Sands and Gila mustang herds, etc.), the Black Hills Wild
Horse Sanctuary, South Dakota (preserving Spanish
mustangs),64 the Lifesavers Wild Horse Sanctuaries near
Lancaster and Twin Oaks, California, the Coyote Canyon
wild horse remnants maintained by various individual
families in southern California, the Dreamcatcher’s wild
horse and burro sanctuary of northern California, the Horse
Power wild horse and burro sanctuary, and the Wild Horse
Spirit Sanctuary, both located in Washoe Valley, western
Nevada. Other sanctuaries would also be contacted
throughout the U.S. Especially important in this regard
would be the long-term holding facilities that have been
contracted to care for thousands of wild horses and burro
that have been displaced from their legal Herd Areas
(BLM) and Territories (USFS) throughout the West. As of
January 2014, these number ca. 55,000 equids. They
represent many unique lineages that have adapted over
many generations to the unique ecosystems they inhabited.
Wherever possible, these should be returned to their
legitimate Herd Areas/Territories or to areas that are
ecologically similar. This would alleviate both the horses
and burros as well as the U.S. taxpayer and above all
restore the long-term viability of the wild herds. Finally, the
United States government could collaborate with its
neighboring nations of Canada and Mexico in restoring
wild horses and burros at viable population levels where
4.2. Final Thoughts
Worldwide, the horse family is declining rapidly.[21, 67-
70] Restored to its ancestral freedom on the North
American continent, any population of horses or burros, in
fact, returns to its ultimate place of origin and long-
standing evolution. Here these animals should be allowed
to regain long-term-viable population levels in regions of
adequate size and containing complete habitats. Thus,
whether horse or burro, their true vigor as a species will be
restored. And in the larger sense, this restoration will be for
the very ancient and magnificent horse family itself.
Wild horses and burros should be declared a UNESCO
World Heritage, as well as the national heritage species
they have already been, in fact, proclaimed by the Wild
Free-Roaming Horses and Burros Act of 1971. Wild horses’
genetics combine early Spanish horses of Andalusian stock
(a combination of Berber, Arab, and Northern European
races) with horses from all over the world. These include
the Bashkir “curlies” brought over by Russians to the
Northwest Pacific. In fact, the hardy wild horses and burros
have much the same diversity and hybrid vigor as
American people. Thus, we Americans can truly say they
are a parallel reflection of ourselves.
Living in the natural world, they are submitted to the
rigors of natural selection that adapt them to both more
constant as well as to changing environmental conditions.
Thus, many adaptive traits emerge that do not manifest in
captivity, where genetic diversity, particularly among
males, is greatly reduced (since even fewer males are
chosen to breed). One great example concerns their
remarkable hoofs. These are kept in perfect, unshod
condition on wild, rocky terrain and greatly assist in the
circulation of blood through a sort of pumping action
involving the suction cup effect of the hoof ’s bottom as the
horse walks or runs. Equids living in the wild become their
own person, so to speak a truly quickened and striving
presence! When people dismiss them as misfits here in
North America, their cradle of evolution, they prove the old
saw: “There are none so blind as they who will not see.”
The author wishes to express his gratitude to the
following individuals and organizations that have helped
with the preparation of this article: Andean Tapir
Fund/Wild Horse and Burro Fund, The Cloud Foundation,
International Society for the Protection of Mustangs and
Burros, Dr. Mary McNichols, Mr. John Brian, biologist T.
Horton, and for editorial assistance, Ms. Susan Madden and
Mr. T. Horton.
Partial List of Horse Fossil Sites (See
Section 3.2.2 for meaning of
1. Ventana Cave, Arizona: two horses from LHOL; one
horse from MHOL; one horse from HIHO;
2. Awatovi, Arizona: one horse from HIHO;
3. Fort Davy Crocket, Colorado: one horse from HIHO;
4. Kin Tl'iish, Colorado: one horse from LHOL;
5. Long House, Colorado: one horse from LHOL;
6. Merina, Colorado: one horse from LHOL;
7. Cemochechobee, Georgia: one horse from LHOL;
8. Calf Island, Massachussetts: one horse from HIHO;
9. Blacktail Cave, Montana: one horse from MHOL;
10. Hoffer, Montana: one horse from LHOL, two horses
from HIHO;
11. Amahami, North Dakota: one horse from LHOL; one
horse from HIHO;
12. Navajo Reservoir Site LA 3430, New Mexico: two
horses from LHOL;
13. Ft. Randall Historic Site, South Dakota: one horse
from LHOL;
14. H.P. Thomas, South Dakota: one horse from HIHO;
one horse from LHOL;
15. Lubbock Lake, Texas: one horse from EMHO, one
horse from MHOL; one horse from LHOL
16. Site 45AS80, Washington: one horse from LHOL;
17. Chief Joseph Dam Site 450K2, Washington: one
horse from HIHO, one horse from LHOL;
18. Chief Joseph Dam Site 450K258, Washington: one
horse from LHOL, two horses from HIHO;
19. Site 48UT370, Wyoming: one horse from MHOL.
Two other sites for which evidence exists for more
recently dated horse fossils are: one site near Rock Springs,
Wyoming (early post-Columbian but still with an intriguing
fossil horse skeleton), 429 YBP; and the Horsethief Cave
fossil site also in Wyoming that has produced a horse femur
dated by thermoluminescent means to 3124 YBP. Similar
records have been reported from Canada and parts of
Mexico, as well as Central and South America.
... See Appendix B for detailed evidence on this all important "fairness issue". ( See also Ganskopp 1984, Berger 1986, National Research Council 2013, Steen Mountain Advisory Council Meeting 2012, Devlin 2018, Hansen et al. 1977, Downer 2014a, Downer 2014b, Wild Horse Freedom Federation 2017. ...
... See Appendix B for detailed evidence on this all important "fairness issue". ( See also Ganskopp 1984, Berger 1986, National Research Council 2013, Steen Mountain Advisory Council Meeting 2012, Devlin 2018, Hansen et al. 1977, Downer 2014a, Downer 2014b, Wild Horse Freedom Federation 2017. ...
... Indeed, BLM admits that it has to periodically transfer horses between Kiger Mustang HMA and Riddle Mountain HMA in order to maintain genetic diversity. However, the level of genetic heterogeneity (genetic variation) is far from what would assure long-term viability/survival (Duncan 1992, Downer 2014; Bureau of Land Management; see also Appendix C). ...
... These officials need to seriously consider my Reserve Design proposal (see Downer, 2014 b & . Reserve Design involves letting the horses and all the natural life community show us how many belong and what true and amazing harmony can be restored. ...
Full-text available
In June of 2020, the author traveled on Highway 50 across Nevada from Carson City to Ely and on to Milford, Utah. He spent about a week making observations of the famed Sulphur Spanish mustangs and their habitat in the Sulphur Herd Management Area (HMA) as well as other wild horse herds and areas. He was joined by fellow conservationist Stephanie Camfield of New Mexico. Twenty-six ecological, 100'-by-20' transects were conducted in the Sulphur HMA. Later the nearby Conger HMA was visited and observations of its wild horses and their habitat were made, including four similar transects. Of the total habitat examined in the Sulphur HMA, it is estimated that 19% needs immediate remedial attention because of damaging impacts that are mainly attributable to livestock and vehicles. Observations of this herd and its habitat does not justify the major BLM-ordered reduction of the rare Sulphur HMA Spanish mustangs to a genetically non-viable level that just occurred in August, 2020. Observations and transects indicated that the Conger HMA herd and habitat is in serious need of restoration. Both HMAs are suffering serious ecological damage due to uncontrolled livestock, vehicle and other impacts. Following the BLM/USGS transect methods (Pellant et al., 2005), for Soils and Site Stability and Hydrologic Function attributes, the sum of percentages for Moderate to Extreme and Extreme to Total is 23.4%, or nearly one fourth, while for the Biotic Integrity attribute, the sum of percentages in the Moderate to Extreme and Extreme to Total is 36.7%, or over a third. Based upon these transects and my visual survey of a much greater area, I urge a significant cut back on livestock and reduction in vehicle impacts, including Off-Highway Vehicles (OHVs) in both HMAs. This is needed to assure truly viable populations of wild horses that are allowed to adapt harmoniously to the ecosystems they inhabit and to stabilize their population by virtue of allowing mature social bands to form and other controls 3 recognized in a sound Reserve Design (Downer, 2014b) approach to wild horse conservation. The wild horses need to receive a much fairer share of forage, water, shelter and other required habitat necessities. Additional observations were made in various wild horse HMAs adjacent to US Highway 50 especially in Nevada.
... These symbionts are well organized for obtaining the resources and favor accompanying hostile plants rather than other plants (Johnson 2010). The invasive plants and their symbionts obstruct the capability of the native community of symbionts to obtain the positions and reduce the acts of native plants indirectly, suggested by the hypothesis of degraded mutualistism (Downer 2014). Growth improvement and survival of exotic seedlings near the natural recognized symbionts is demonstrated by the positive feedback (Bever et al. 2010). ...
In interactions between plants and soil, microorganisms have significant roles. Ecological stability is contributed by the biogeochemical cycling of elements. An emerging body of research is distinguishing the impacts that root-associated microbial communities can have on plant fitness and growth. Rocks and minerals are weathered by the activities of plants, which exude various types of hormones, with a crucial role in the supply of organic matter and formation of soils. Various types of plant species have distinctive biological characteristics that show constraint to precise soil types. Plant–microbe interactions in soil are contributing to a new, microbially based perspective on plant community and ecology. These microorganisms are soil dwellers, diverse, and their interactions with plants vary with respect to specificity, environmental heterogeneity, and fitness impact. The key influences on plant community structure and dynamics are effected by two microbial procedures: microbial intervention of niche diversity in resource use and response dynamics among the soil community and plants. The hypothesis of niche diversity is based on various interpretations that the nutrients of soil are found in different chemical forms: the plant requires accessing these enzymes and nutrients, and the microorganisms of the soil are a major source of these enzymes. Plant–microbe interactions are a significant establishing force for extensive spatial gradients in species abundance. The positive response (a homogenizing force) and negative response (a diversifying force) of virtual balance may contribute to detected latitudinal (and altitudinal) diversity patterns. The microbially based perception for the ecology of plants promises to contribute to our understanding of long-standing issues in ecology and to disclose new areas of future investigation.
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Horses and burros, including especially wild, naturally living ones, play a major role in combatting Global Warming and do this in a variety of ways. One of these concerns their superior ability to sequester, or "lock away," Carbon. They remove Carbon from the atmosphere, where, in the form of carbon dioxide, methane and other heat-trapping gases, this element accelerates a dangerous, oven-like increase in temperatures on our entire planet Earth. All members of the horse family Equidae, as well as their Mammalian Order Perissodactyla, play this same vital and life-saving role. This includes also the various onagers, zebras, tapirs and rhinoceroses of the world, nearly all of which are listed as threatened or endangered with extinction in the Red List put out by the World Conservation Union's (IUCN) Species Survival Commission (2021). As a member of the IUCN SSC, I have written action plans and species resumes to mount a global effort to save and restore these very important species together with their appropriate habitats. (See also tapir.) Much of the superior ability of the horses and burros to sequester Carbon is related to their special digestive system. This is different from the ruminant digestive system of many other plant eaters, or herbivores, in our world. These include many millions of cattle, sheep, goats, deer, elk, etc., that are overly forced in excessive numbers onto life communities, or ecosystems, the world over, including in the United States. Horses and burros possess a monogastric, cecal-fermenting digestive system that is less complex than that of the multi-stomach, rumen-fermenting digestive system of ruminant herbivores. As a consequence , these equids do not as thoroughly decompose their food as do ruminants. As a consequence, the chemistry of equid droppings is more organically intact and complex. This fact has enormously positive consequences for habitats. One of the chief advantages is that equine feces contribute to more vital soils by augmenting their humus content. As many gardeners know, humus is crucial to healthy soils, making these more nutrient-rich and water-retaining. Indeed, the renowned San Francisco Botanical Garden has soils that were enriched from sandy beach loam by mixing horse manure clear back in the 1870s and horse droppings continue to play a major part in keeping this garden so exuberant today. The health of ecosystems depends upon healthy plant life, which depends upon healthy soils. Horses create more robust soils that cause grasses, forbs, bushes and trees to flourish when adequate water, healthy air and sunshine is added into the mixture. In regions where they belong, horses have been proven to allow a much greater diversity of species of both plants and animals together with their interrelated roles in the life community. This gives greater resistance and resilience to horse-containing ecosystems. This has been proven here in North America and in many places all over the world. One prime example concerns the restoration of Spanish Retuerta horses in overgrazed ecosystems in Andalusia. This ongoing program is restoring ecosystems that had been overgrazed by livestock for
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The study of bone growth marks (BGMs) and other histological traits of bone tissue provides insights into the life history of present and past organisms. Important life history traits like longevity or age at maturity, which could be inferred from the analysis of these features, form the basis for estimations of demographic parameters that are essential in ecological and evolutionary studies of vertebrates. Here, we study the intraskeletal histological variability in an ontogenetic series of Asiatic wild ass (Equus hemionus) in order to assess the suitability of several skeletal elements to reconstruct the life history strategy of the species. Bone tissue types, vascular canal orientation and BGMs have been analyzed in 35 cross-sections of femur, tibia and metapodial bones of 9 individuals of different sexes, ages and habitats. Our results show that the number of BGMs recorded by the different limb bones varies within the same specimen. Our study supports that the femur is the most reliable bone for skeletochronology, as already suggested. Our findings also challenge traditional beliefs with regard to the meaning of deposition of the external fundamental system (EFS). In the Asiatic wild ass, this bone tissue is deposited some time after skeletal maturity and, in the case of the femora, coinciding with the reproductive maturity of the species. The results obtained from this research are not only relevant for future studies in fossil Equus, but could also contribute to improve the conservation strategies of threatened equid species.
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