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Distribution, natural history, and impacts of the introduced green iguana (Iguana iguana) in Florida

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2IGUANA • VOLUME 14, NUMBER 3 • SEPTEMBER 2007
An adult male Green Iguana (Iguana iguana) basking on a dock in Hollywood, Broward County, Florida.
KRYSKO, ET AL
ANTHONY FLANAGAN
IGUANA • VOLUME 14, NUMBER 3 • SEPTEMBER 2007 3
Introduction
The Green Iguana, Iguana iguana (Linnaeus 1758), was first
reported in the 1960s in Florida as occurring, but not
breeding, on the southeastern coast from Hialeah, Coral Gables,
and Key Biscayne in Miami-Dade County. Over the next few
decades, many residents enjoyed watching these large exotic
lizards, allowing them to roam unmolested on their properties,
and at times even feeding them. By the mid-1990s, however,
many residents’ attitudes changed as iguana populations
exploded, often becoming a nuisance to humans and having a
negative impact on the environment. Although many authors
have documented the occurrence of I. iguana populations in
Florida, none fully illustrate this species’ expansive geographic
distribution or remark on its potential effects. Herein, we doc-
ument the current geographic distribution using voucher spec-
imens and field observations, potential ecological impacts, and
nuisance value of this non-native species in Florida.
Materials and Methods
Locality records of Iguana iguana were obtained from the liter-
ature and from systematic collections throughout the United
States. Fieldwork was conducted from May 1992 through
December 2006; I. iguana were collected by hand, noosing, and
shooting small tapered corks from a blowgun (for neonates
only). In addition, photographs were taken and used as vouch-
ers. Specimens were deposited in East Tennessee State University
(ETMNH), Indiana State University Vertebrate Collection
(ISUVC), Florida Museum of Natural History, University of
Florida (UF), United States National Museum (USNM), and
Yale Peabody Museum (YPM). All records with locality data
were plotted using ArcView v. 3.2 (ESRI).
Distribution and History of Introductions
The native range of Iguana iguana extends from southern
Mexico to central Brazil and Bolivia (Lazell 1973, Savage 2002),
Distribution, Natural History,
and Impacts of the Introduced
Green Iguana (Iguana iguana) in Florida
Kenneth L. Krysko1, Kevin M. Enge2, Ellen M. Donlan3, Jason C. Seitz4, and Elizabeth A. Golden5
1Florida Museum of Natural History, Division of Herpetology, University of Florida, Dickinson Hall,
Museum Road, Gainesville, Florida 32611-7800, USA (kenneyk@flmnh.ufl.edu)
2Florida Fish and Wildlife Conservation Commission, Joe Budd Wildlife Field Office,
5300 High Bridge Road, Quincy, Florida 32351, USA (kevin.enge@myfwc.com)
3Vegetation Management, South Florida Water Management District, 3301 Gun Club Road, West Palm Beach, Florida 33406, USA (edonlan@sfwmd.gov)
4Creative Environmental Solutions, Inc., 1425 NW 6th Street, Gainesville, Florida 32601, USA (floridasawfish@yahoo.com)
5Bill Baggs Cape Florida State Park, 1200 South Crandon Boulevard, Key Biscayne, Florida 33149, USA (elizabeth.golden@dep.state.fl.us)
Abstract.—In this article, we document the geographic distribution, reproduction, potential ecological impacts, and nuisance value of
the non-native Green Iguana (Iguana iguana) in Florida. We further provide management recommendations for control of this species
in Florida. Locality records of I. iguana were obtained via the literature and both photographic and specimen vouchers, and also from
the field, where specimens were collected and observations made from May 1992 through December 2006. We compiled 3,169 records
of I. iguana in Florida. Iguana iguana was first reported (but not breeding) in Florida in 1966 from Miami-Dade County; however, it is
now reproducing and established in much of southern Florida, including many Florida Keys. We observed I. iguana mating as early as
December and as late as April. Ovipositioning usually takes place in sandy areas. Females were found to have vitellogenic follicles in
November, December, and February; carried oviducal eggs between February and April; and we found a single clutch of 41 eggs that
was oviposited in April. Neonates were observed from May through August. Iguana iguana feed on a variety of vegetation, as well as
insects, tree snails, and possibly small mammals. This species causes considerable damage to landscape vegetation and often is consid-
ered a nuisance by land managers and property owners. Burrowing by Green Iguanas causes erosion and undermines sidewalks, foun-
dations, seawalls, berms, and canal banks. They also force vehicular traffic to brake; deposit unsightly and unhygienic defecations on
moored boats, seawalls, docks, porches, decks, pool platforms, and inside swimming pools; potentially act as seed dispersers for invasive
plant species; and may transmit Salmonella to humans. A number of steps can be taken by Florida landowners to help control I. iguana
in the state: First, vegetation selected for landscaping should lack the showy flowers and colorful fruits that are eaten preferentially by
iguanas. Second, trapping and removing live lizards can be undertaken using live traps (e.g., Havahart, Tomahawk), snare traps, and
nooses. Third, artificial nesting sites can be easily constructed and monitored during the reproductive season so that iguana eggs can be
removed and destroyed. Finally, before purchasing pet iguanas, prospective owners should be educated on the life history details (e.g.,
large adult size, potential to inflict painful wounds, etc.) and complex husbandry requirements of this lizard, and be made aware that
releasing this or any other non-native animal into the wild is illegal in Florida.
GREEN IGUNA IN FLORIDA
4IGUANA • VOLUME 14, NUMBER 3 • SEPTEMBER 2007 KRYSKO, ET AL
including the Caribbean islands of Cozumel (J.C. Seitz, pers.
obs.), San Andrés and Providencia, Roatán, Utila, Swan Island,
Cayo Icacos, Curaçao, St. Vincent and the Grenadines,
Grenada, Îles des Saintes, Montserrat, Saba, St. Lucia, and
Trinidad and Tobago (Bakhuis 1982, Murphy 1997, Schwartz
and Henderson 1991). Green Iguanas have been introduced in
Grand Cayman (Seidel and Franz 1994), Guadeloupe (Lever
2003), St. Martin/St. Maarten (Powell et al. 2005), Puerto Rico
(Thomas 1999), Hawaii (McKeown 1996), the southern Rio
Grande Valley in Texas (Meshaka et al. 2004a, Bartlett and
Bartlett 2006), and Florida (Wilson and Porras 1983). The ori-
gin of the U.S. Virgin Islands population has been disputed for
some time (Lazell 1973), with some authors contending that
iguanas were introduced by man (see Thomas 1999).
We compiled 3,169 records of I. iguana from southern
Florida; 1,088 of these represent preserved specimens and pho-
tographic vouchers collected between 1965 and 2006
(Appendix) and 2,081 represent field observations. The species
is widely established along the Atlantic Coast in Broward,
Martin, Miami-Dade, Monroe, and Palm Beach counties, and
along the Gulf Coast in Collier and Lee counties. Although I.
iguana has been found farther north in Alachua, Highlands,
Hillsborough, Indian River, and St. Lucie counties, no voucher
specimens exist for these scattered localities (except Alachua, UF
122514) and these individuals are unlikely to represent estab-
lished populations due to low winter temperatures. 1
King and Krakauer (1966) recorded the first Florida
voucher specimen (UF 22910, Table 1) collected in 1965 from
Coral Gables, and subsequently reported I. iguana as an estab-
lished, but non-breeding species from four separate areas in
Miami-Dade County: East 7th Avenue and West 27th Street in
Hialeah, Caballero Boulevard and Hardee Road in Coral
Gables, southwest corner of Miami International Airport, and
Key Biscayne. More than 300 individuals were released between
May and September 1964 at the Hialeah site (King and
Krakauer 1966). Wilson and Porras (1983) reported I. iguana
from the Miami Seaquarium on Virginia Key, and Butterfield et
al. (1997) speculated that this species had probably been breed-
ing in Miami since around 1980. Although I. iguana is occasion-
ally observed in Everglades National Park (e.g., nine sightings in
1995–2004), a population has apparently not become estab-
lished, possibly because of the presence of potential predators
and competitors, and the lack of suitable nesting sites (Meshaka
et al. 2000, 2004a, 2004b). Iguana iguana was first documented
from Broward County in Davie (Townsend et al. 2002), and
Palm Beach County in Loxahatchee National Wildlife Refuge
and Palm Beach Gardens (Krysko et al. 2005). We pho-
tographed this species in 2006 in Port Mayaca, Martin County.
Bartlett (1980) first observed I. iguana in southwestern
Florida in Collier County, but did not identify a specific local-
ity. Krysko et al. (2005) documented the first voucher specimens
from Collier County (collected as early as 1998) in Golden
Gate. Iguana iguana has been established for at least a decade on
Marco Island (N. Richie, pers. comm.), and in 2005 this species
was observed along the mangrove fringe between Goodland and
Goodland Bay (K. Laakkonen, pers. comm.), the Florida
Panther National Wildlife Refuge (D. Giardina, pers. comm.),
Copeland (within Fakahatchee Strand Preserve State Park), and
in Naples. In Lee County, I. iguana has been reported from
Cape Coral (Bartlett and Bartlett 1999, Krysko et al. 2005), and
Bonita Springs between Williams Road and the Imperial River
since about 2000 (Spinner 2005).
Duquesnel (1998) first observed I. iguana in the upper
Florida Keys at John Pennekamp Coral Reef State Park, Key
Largo. Krysko et al. (2005) documented this species in the lower
Florida Keys from (east to west) Little Torch and Sugarloaf keys,
and Stock Island. More recently, these findings have been aug-
mented with voucher specimens from Key Largo, Windley Key,
Big Pine Key, Vaca Key, and Key West; and with observations
only from Plantation, Duck, Little Crawl, Bahia Honda, Middle
Torch, Summerland, Cudjoe, Lower Sugarloaf, Big Coppitt, and
Boca Chica keys.
Food Habits and Predators
Neonate and juvenile Iguana iguana feed on vegetation (i.e., new
shoots, leaves, blossoms, and fruits) and insects such as grasshop-
pers (Hirth 1963). In addition to these items, adults have been
reported to feed on bird eggs (Lazell 1973) and carrion (Loftin
and Tyson 1965). In Florida, neonates and juveniles feed on veg-
etation, insects, and tree snails (Townsend et al. 2005), whereas
adults are primarily herbivorous, but may take additional items
as well. A juvenile I. iguana appeared to be feeding on Firebush
(Hamelia patens) fruits in a Naples garden (J. Schmid, pers.
comm.). Fecal contents of a Homestead, Florida individual
included flowers, leaves, and fruits from non-native Jasmine
(Jasminum sp.) and Washington Fan Palms (Washingtonia
robusta; Meshaka et al. 2004b). At Bill Baggs Cape Florida State
Park (BBCF) on the southern tip of Key Biscayne, we have
observed I. iguana feeding on Nicker Bean (Caesalpinia bonduc),
Records (N = 3,169) of Green Iguanas (Iguana iguana) in southern
Florida. Open circles indicate preserved specimens and photographic
vouchers (N = 1,088) collected between 1965 and 2006, circles with
central dots indicate observations (N = 2,081). A dot may represent
more than one record.
and we have collected specimens that had eaten tree snails
(Drymaeus multilineatus; see Townsend et al. 2005) and an adult
(UF 137405) found dead-on-road (DOR) with mammal hair
in its mouth. At Crandon Park on Key Biscayne, I. iguana eats
cracked corn supplied to captive waterfowl, and adults removed
from an overbrowsed area defecated rat (Rattus sp.) hair (G.
Ward, pers. comm.). Two Green Iguanas were observed feeding
on a Spanish Stopper (Eugenia foetida) just before basking on a
Strangler Fig (Ficus aurea; J.G. Duquesnel, pers. comm.). 2,3
In its native range, I. iguana is preyed upon by a variety of
reptilian, avian, and mammalian species. In Venezuela, juveniles
that had emerged by the thousands over a 14-day period were
preyed upon by three crocodilian, two snake, three teiid lizard,
nine accipiter, four falcon, one owl, three heron, three cuckoo,
two passerine, and six mammalian species, including domestic
dog (Canis familiaris) and cat (Felis domesticus; Antonio Rivas et
al. 1998). Some of the predators identified in its native range
also occur in southern Florida: Boa Constrictor (Boa constrictor),
Spectacled Caiman (Caiman crocodilus), American Crocodile
(Crocodylus acutus), Giant Ameiva (Ameiva ameiva), Barn Owl
(Tyto alba), Broad-winged Hawk (Buteo platypterus), Swallow-
tailed Kite (Elanoides forficatus), White-tailed Kite (Elanus leu-
curus), Osprey (Pandion haliaetus), American Kestrel (Falco
sparverius), Crested Caracara (Caracara cheriway), Great Egret
(Ardea alba), and Smooth-billed Ani (Crotophaga ani; Antonio
Rivas et al. 1998, Greene et al. 1978, Swanson 1950, Wunderle
1981). Cats, Caracaras, and Kestrels are among the most com-
mon predators in Venezuela (Antonio Rivas et al. 1998).
Juvenile Green Iguanas in Florida are eaten by the Florida
Burrowing Owl (Athene cunicularia floridana), Yellow-crowned
Night-heron (Nyctanassa violacea), Yellow Rat Snake (Elaphe
obsoleta), and domestic dog (Engeman et al. 2005b, McKie et
al. 2005, Meshaka et al. 2004b). Potential predators of iguana
eggs are the Raccoon (Procyon lotor), Spotted Skunk (Spilogale
putorius), Fish Crow (Corvus ossifragus), Black (Coragyps atratus)
and Turkey (Cathartes aura) Vultures, feral pig (Sus scrofa), and
domestic dog (Hirth 1963, Sexton 1975).
Eggs and young Green Iguanas possibly are eaten by a vari-
ety of native wildlife species in Florida, and they might provide
an important source of food, particularly in areas with dense
iguana populations and few remaining native prey species.
Neonate I. iguana are frequently found on the ground, in shrubs,
or low in trees (Henderson 1974, Hirth 1963, Swanson 1950),
exposing them to different predators than adults, which are usu-
ally high in trees. In Florida, once I. iguana reaches about 60 cm
TL, it has few adversaries except humans, possibly domestic dogs,
American Alligators (Alligator mississippiensis; see Kern 2004), and
American Crocodiles, and is frequently found in open areas.
Green Iguanas of all sizes are collected by humans for the pet
trade, nuisance control, and human consumption. 4,5
Reproduction
In its native range, adult male Green Iguanas have larger home
ranges (up to 9,000 m2) than females and juveniles (Rand et al.
1989). In Costa Rica, mating occurs in October–November
(possibly December in Tortuguero) during the dry season
(Hirth 1963). Females are known to travel up to several kilo-
meters to reach suitable nesting sites, where they nest either
alone or communally (Alvarez del Toro 1960, Rand 1968,
Rand and Dugan 1983). Nesting sites are usually in sandy open
areas, such as riverbanks, islands, or beaches (Burghardt et al.
1977, Campos 2004, Haller and Rodrigues 2005, Hirth 1963),
and females exhibit nesting site fidelity (Bock et al. 1985). In
Panama, I. iguana sometimes shares nesting sites with American
Crocodiles, whose nest defense behavior may disrupt iguana
nesting activities (Bock and Rand 1989); similarly in
Honduras, iguanas eggs have been uncovered in a Spectacled
Caiman nest (Carr 1953). Female I. iguana typically dig an egg
chamber 10–120 cm deep and 100–463 cm long (Haller and
Rodrigues 2005, Rand 1968, Rand and Dugan 1980), but
complex nests shared by multiple females may have a system of
interconnecting tunnels up to 24 m long (Rand and Dugan
1983). Female I. iguana plug the nest tunnel, which is 10–15
cm wide and 7–10 cm high, with substrate using the snout
(Rand 1968). Ovipositioning of 10–71 eggs (Campos 2004,
Fitch 1985, Haller and Rodrigues 2005, Hirth 1963, Rand
1968, Swanson 1950) occurs in late afternoon (rarely in the
morning) between early February and April in Mexico and
Central America (Alvarado et al. 1995, Alvarez del Toro 1960,
Bock and Rand 1989, Hirth 1963, Swanson 1950). Nesting
IGUANA • VOLUME 14, NUMBER 3 • SEPTEMBER 2007 5GREEN IGUNA IN FLORIDA
A juvenile Green Iguana (Iguana iguana) on a non-native Golden
Dewdrop (Duranta erecta) in Naples, Collier County, Florida (photo-
graphic voucher UF 146274). This iguana appeared to be foraging on
fruit from an adjacent Firebush (Hamelia patens).
JEFFREY R. SCHMID
Two Green Iguanas (Iguana iguana) on a Strangler Fig (Ficus aurea) on
Key Largo, Monroe County, Florida (photographic voucher UF
149986). These iguanas were observed feeding on adjacent Spanish
Stopper (Eugenia foetida).
JAMES G. DUQUESNEL
may take place from December to February in the Lesser
Antilles (Lazell 1973), from late January to March in Colombia
(Muñoz et al. 2003), and September to December in Brazil
(Campos 2004, Haller and Rodrigues 2005). Incubation of
eggs takes approximately three months (Alvarez del Toro 1960;
Swanson 1950). In southern Florida, we observed Green
Iguana mating behavior, including male combat, as early as
December and lasting through April. Ovipositioning usually
takes place in sandy areas, but one known female nested in a
mulch pile on Key Largo (J. Duquesnel, pers. comm.). We col-
lected: (1) Four females with vitellogenic follicles (mean = 30.2
± 4.5 mm, 20–42 mm) from November, December, and
February; (2) 22 females with oviducal eggs (mean = 35.5 ± 2.9
mm, 12–62 mm) between February and April; and (3) A sin-
gle clutch of 41 eggs oviposited in April. Neonates are observed
from May to August in both the southern peninsula and
Florida Keys.
Nuisance Problems in Florida
From the 1960s through the 1980s, many residents in Miami
enjoyed watching the large exotic Iguana iguana, allowing them
to roam unmolested on their properties and at times even feed-
ing them. Prior to Hurricane Andrew in 1992, I. iguana was not
generally considered a nuisance species, but populations
exploded in the 1990s in many areas of southeastern Florida. In
1992, a large reptile dealer in Hollywood, Broward County, pur-
chased few I. iguana that were captured locally (R. Van
Nostrand, pers. comm.); now this species can be captured by the
hundreds in this county and in adjacent Palm Beach County to
the north. According to newspaper articles since 2003, I. iguana
populations have increased markedly to nuisance levels in
Pompano Beach, Pembroke Pines, Dania Beach, Plantation,
Davie, Delray Beach, and Boca Raton. In the past few years, I.
iguana began appearing in large numbers in the Keys, sometimes
crossing roads and forcing traffic to brake along U.S. 1, which
prompted the Florida Keys Invasive Species Task Force to solicit
advice from the Florida Fish and Wildlife Conservation
Commission (FWC) and Florida Museum of Natural History
(FLMNH) on how to control or eradicate these populations. 6,7
On Key Biscayne, the post-Hurricane Andrew I. iguana
population explosion was possibly due to opening up of the
canopy, subsequent replanting of non-native landscape vegeta-
tion favored as food by iguanas (see Meshaka et al. 2004a), and
creation of suitable nesting areas. This aggressive replanting of
ornamental vegetation occurred throughout southeastern Florida
after the widespread destruction caused by the hurricane. Before
the hurricane, Bill Baggs Cape Florida State Park (BBCF) was
extensively vegetated by non-native Australian Pines (Casuarina
equisetifolia), thus iguana food and iguanas were scarce. After
most of the Australian Pines were destroyed by the hurricane,
BBCF park staff eventually began efforts to restore natural habi-
tats and native vegetation. Fallen trees and other hurricane debris
at BBCF and the county-owned Crandon Park to the north on
Key Biscayne were mulched and bulldozed into piles, creating
exposed, well-drained mounds that served as ideal sites for I.
iguana to dig nesting burrows. Iguana iguana became so com-
mon at BBCF that, in 2003 alone, 824 iguanas were removed,
mostly by one of us (EMD; see also Townsend et al. 2003), who
also compiled these records into the park database. Meshaka et
al. (2004a) attempted to illustrate increasing and high popula-
tion densities of I. iguana at BBCF based solely on records main-
tained in the park database from 1 July 1998 through 30 June
2003 (reported therein as 0, 0, 1, 12, 384, respectively); however,
the park database records are incomplete. Although we also
believe that I. iguana has increased there (and other areas) since
the late 1990s, the values reported for 2003 are elevated solely
because of the collecting effort by EMD, who focused on remov-
ing non-native wildlife beginning in 2003 and ending upon leav-
6IGUANA • VOLUME 14, NUMBER 3 • SEPTEMBER 2007 KRYSKO, ET AL
Two adult male Green Iguanas (Iguana iguana) fighting on 24
February 2004 on a dock in Hollywood, Broward County, Florida.
ANTHONY FLANAGAN
Two Green Iguanas (Iguana iguana) being fed by humans on a dock on
Sugarloaf Key, Monroe County, Florida (photographic voucher UF 131549).
KENNETH L. KRYSKO
Green Iguanas (Iguana iguana) basking on a dock in Hollywood,
Broward County, Florida. Note iguana feces covering the deck.
ANTHONY FLANAGAN
IGUANA • VOLUME 14, NUMBER 3 • SEPTEMBER 2007 7
ing BBCF in March 2004. If one were to calculate and expand
on the actual numbers of I. iguana removed from BBCF from
1998 through 2006 (0, 0, 0, 9, 57, 824, 265, 189, and 89,
respectively), after the point in which EMD left BBCF, this
would erroneously illustrate a severe population crash.
Iguana iguana can cause considerable damage to residential
and commercial landscape vegetation and is now often consid-
ered a nuisance by land managers and property owners, who
sometimes have to install wire mesh or even electric fences
around herbs, shrubs, and trees to protect them from these vora-
cious lizards. Vulnerable young trees, and older trees with foliage
or flowers particularly attractive to iguanas, can be protected
from climbing lizards by encasing part of their trunks with sheet
metal, as long as other trees are not within leaping distance. For
many years, staff at Fairchild Tropical Botanic Garden in Miami
tolerated I. iguana and prohibited their removal, until escalating
populations started eating prized orchids (Orchidaceae) and the
historic Hibiscus (Hibiscus spp.) garden was overgrazed to the
ground and had to be relocated to a safer location. Other favored
food plants include Impatiens (Impatiens spp.), Rose (Rosa spp.),
Nasturtium (Tropaeolum majus), Caladium (Caladium spp.),
Purple Heart (Tradescantia [Setcreasea] pallida), Bougainvillea
(Bougainvillea spp.), and Hong Kong Orchid Tree (Bauhinia
blakeana; see Kern 2004, Johnson 2006). Iguana iguana will eat
most fruits (except citrus) and flowers, tender new growth, and
almost anything planted in a vegetable garden (Kern 2004). In
the 2000s, I. iguana ate most of the recently planted butterfly
garden at the Key Deer National Wildlife Refuge on Big Pine
Key (C. Bergh, pers. comm.). 8
Iguana iguana also is considered a nuisance by homeown-
ers in part due to unsightly and unhygienic defecations on
docks, moored boats, seawalls, porches, decks, pool platforms
and inside swimming pools. Iguana iguana can transmit the
infectious bacterium Salmonella to humans through their feces,
which conceivably could occur if iguanas defecate in swimming
pools or on food while people are eating outside. Some I. iguana
dig burrows that are used as refugia, which can be accompanied
by erosion that undermines sidewalks, foundations, seawalls,
berms, and canal banks (Kern 2004, Johnson 2006). Although
I. iguana usually uses burrows only as temporary refugia when
away from water, over 100 iguana burrows (up to 4.5 m long)
were observed in a seasonally flooded borrow pit in Venezuela,
which were used as nocturnal refugia despite the presence of
numerous trees (Rodda and Burghardt 1985). In treeless habi-
tats in Florida, such as cleared canal banks and vacant lots, nor-
mally arboreal lizards seek shelter in burrows, culverts, drainage
pipes, and rock or debris piles.
Large I. iguana basking on airport runways could pose a
hazard to planes. At least five known records document airplanes
colliding with iguanas at the international airport in San Juan,
Puerto Rico, where this species was introduced, and large igua-
nas would have a relative hazard score equivalent to ducks and
pelicans (Engeman et al. 2005a). Iguana iguana also can be
observed basking and grazing on golf course fairways in Florida,
but these lizards generally do not pose a hazard to golfers.
Iguana iguana is responsible for more complaints to the
FWC than any other non-native reptilian species in Florida.
Numbers of complaints continue to increase as iguanas expand
their range into new areas, and additional homeowners experi-
ence the dubious thrill of having the reptilian version of a sheep
devouring their landscape. Although many people enjoy watch-
ing I. iguana as long as they do not damage valued plants or
property, many other people are afraid of these large lizards,
especially visitors or new residents, who are not accustomed to
such large prehistoric-looking animals living in their neighbor-
GREEN IGUNA IN FLORIDA
Residence on Big Pine Key, Monroe County, Florida, with wire mesh
installed around flowering plants to protect against Green Iguanas
(Iguana iguana).
KENNETH L. KRYSKO
Adult male Green Iguana (Iguana iguana) above a culvert on a canal
bank along U.S. 27 in Medley, Miami-Dade County, Florida (photo-
graphic voucher UF 150123).
KEVIN M. ENGE
hood. Neighbors who were once friendly to each other have
even become rivals and no longer speak, as some families decide
to feed and protect iguanas while other families want to rid these
lizards from their properties (C.D. May, pers. comm.).
Nonetheless, I. iguana will continue to be a common sight in
neighborhoods because of the tolerance of some residents who
feed them, coupled with a scarcity of predators, abundance of
palatable ornamental vegetation (some vegetation with thorns
may ward off potential predators), sunny nesting sites, and the
presence of canals, lakes, and swimming pools for drinking water
and escape cover. Furthermore, the profusion of man-made
canals serve as dispersal corridors that allow iguanas to colonize
new areas. 9–11
Potential Impacts on Other Species
On Marco Island, Iguana iguana occasionally uses burrows of
the Florida Burrowing Owl (N. Richie, pers. comm.), a “Species
of Special Concern” in Florida. At Crandon Park, I. iguana
sometimes shares the same burrow as another non-native species,
the Black Spiny-tailed Iguana (Ctenosaura similis), but most
Green Iguanas utilize trees, particularly those in and around
ponds and canals. The stomach of a juvenile I. iguana from Key
Biscayne contained 12 tree snails (Drymaeus multilineatus), sug-
gesting that it had selectively eaten them (Townsend et al. 2005).
This snail species is common; however, iguanas could potentially
impact other more rare tree snails (Townsend et al. 2005).
The species composition of the plant community might
eventually be altered in areas with dense populations of I. iguana
due to excessive grazing and defoliation of vegetation, resulting
in death or lack of reproduction. In Mexico, I. iguana helps
maintain forest diversity by consuming and dispersing seeds of
many tree species (Morales-Mávil 1997). Iguana iguana is selec-
tive in its diet, and ingested seeds typically have higher germina-
tion rates than uneaten seeds (Benítez-Malvido et al. 2003). In
Florida, I. iguana may be an important seed disperser of non-
native invasive plant species, carrying seeds from people’s yards
into adjacent natural areas and hindering invasive vegetation
control efforts. Iguana iguana at BBCF feed on Nicker Bean, an
important food plant for larvae of the Endangered Miami Blue
Butterfly (Hemiargus thomasi bethunebakeri).
Population Control in Florida
Iguana iguana is now common in many urban areas of the
southern peninsula and Florida Keys, and may be flourishing in
larger natural areas of coastal Florida. Green Iguanas are
extremely popular in the pet trade and sometimes escape or are
intentionally (and illegally) released by owners when they grow
too large. Many pet enthusiasts are unaware (or unwilling to
accept) that releasing non-native animals, including I. iguana, in
Florida is illegal and potentially detrimental to the environment.
Future illegal introductions of non-native animals can be ame-
liorated by incorporating pet owner education into the invasive
species management process. Prospective iguana owners should
be educated on the life history details (e.g., large size of adults,
potential for inflicting painful wounds, etc.) and the complex
husbandry requirements of this species before a purchase. In an
attempt to facilitate disposal of unwanted exotic pets, the FWC
now allows people to return animals (as long as they do not
8IGUANA • VOLUME 14, NUMBER 3 • SEPTEMBER 2007 KRYSKO, ET AL
Two non-native Green Iguanas (Iguana iguana) and a non-native Red-
eared Slider (Trachemys scripta elegans) on non-native Melaleuca
(Melaleuca quinquenervia) along a canal in Opa-Locka, Miami-Dade
County, Florida (photographic voucher UF 150122). Two discarded
automobile tires and other debris litter the man-made canal bank.
KEVIN M. ENGE
Juvenile Green Iguana (Iguana iguana) on a non-native Silk Floss
(Chorisia speciosa) tree in Lake Worth, Palm Beach County, Florida
(photographic voucher UF 149868).
CARL MAY
Adult male Green Iguana (Iguana iguana) at the front door of a resi-
dence in Fort Worth, Palm Beach County, Florida.
CARL MAY
IGUANA • VOLUME 14, NUMBER 3 • SEPTEMBER 2007 9GREEN IGUNA IN FLORIDA
profit from the transaction by receiving more money than what
was originally paid) to the pet store where purchased without
requiring a costly license to sell wildlife.
Iguana iguana populations at the northern extent of their
introduced range in Florida, as well as individual escapees far-
ther north, are controlled by cold winter temperatures, except
when thermal refugia or urban heat islands are available. When
temperatures drop below 50 ºF, sluggish iguanas can be easily
plucked from trees or collected after falling from trees, especially
at night or on overcast days when basking does not increase
body temperature quickly. Well-established populations in
southern Florida appear to have exceeded the point of human
control, and many animal control officers and nuisance trappers
no longer respond to iguana complaints. Even if removal of I.
iguana is successful, more lizards will repopulate the site from
adjacent areas or when eggs hatch. Some private trappers charge
upwards of $100 to visit an iguana-infested site, and they usu-
ally will not guarantee success in catching and removing lizards.
However, David Johnson, “The Iguana Trapper,” claims to spe-
cialize in removing I. iguana from overpopulated residences and
subdivisions (Johnson 2006). During the past four years in his
Pelican Harbor neighborhood along the C-15 Canal in south-
ern Palm Beach County, Johnson (2006) has removed 406 igua-
nas, and during one week in April 2006, he caught 54 iguanas
at one residence in Pompano Beach. Some residents have taken
matters into their own hands; because I. iguana is a non-native
species, it is not afforded protection in Florida, and it is legal to
catch, trap, and humanely kill these lizards. However, permits
or permission must be obtained before collecting wildlife,
including non-native species, from a county, state, or national
park and other public land. Once a Green Iguana is captured, it
cannot legally be released again in Florida, limiting the captor to
choose between killing the iguana humanely, keeping it in cap-
tivity, or selling it. Selling iguanas is no longer lucrative due to
the availability of inexpensive farm-raised iguanas from Latin
America; some pet stores sell imported neonate iguanas for less
than $10 each. Wild-caught adult Green Iguanas seldom
become tame, but zoos and other exhibits are sometimes inter-
ested in acquiring large individuals (especially orange-colored
males) for display purposes, and foreign buyers may pay up to
$300 for exceptional specimens (G. Ward, pers. comm.). 12
Trapping methods for I. iguana include the use of live traps
(e.g., Havahart, Tomahawk) baited with fruit, such as bananas
or mangoes, or locking snares that can be set during the daytime
at burrow entrances, at holes under fences, or along seawalls
(Kern 2004), canals, and ponds. Johnson (2006) used a semicir-
cular mesh trap with a snare at each end (D-I-Y trap) and bait
in the center. However, the most common capture method is by
noosing with a long pole, especially while lizards are sleeping at
night or torpid during cold weather. Some commercial I. iguana
catchers use boats to noose lizards from trees at night, sometimes
stretching out nets to catch iguanas jumping from trees to the
water below (G. Ward, pers. comm.). Persistent harassment may
encourage I. iguana to move to the next-door neighbor’s yard;
this can be accomplished by launching pebbles or palm fruits at
them using a slingshot (Kern 2004), spraying them with a hose,
or through the use of loud vocalizations on the part of a person
or a dog combined with quickly approaching the lizard.
Shooting firearms is outlawed in residential areas. 13
Over the past few years, we have established a cooperative
effort with personnel at Crandon Park on Key Biscayne to
reduce their abundant I. iguana population. Despite our efforts
and those of commercial collectors, who have additionally
removed hundreds of iguanas annually, this species is still a com-
mon sight. People have been caught illegally releasing their pet
iguanas at Crandon Park because they thought it was an “iguana
nursery.” “Iguana crossing” signs were once posted on Key
Biscayne to advise motorists of a potential driving hazard. Over
time, heavily harvested I. iguana populations can be expected to
have lower densities, smaller individuals, and smaller clutch sizes
than unharvested populations (Muñoz et al. 2003).
Female Green Iguanas are known to travel up to several
kilometers to nest (see Alvarez del Toro 1960; Rand 1968; Rand
and Dugan 1983), suggesting that females return to the same
suitable nesting sites year after year. Desirable nesting sites can
be heavily used by females. A clearing about 6 x 7 m in size on
a 0.3-ha islet (not normally inhabited by I. iguana) in a
Panamanian lake attracted as many as 150–200 females annu-
ally (Burghardt et al. 1977). In the Florida Keys, where I. iguana
is expanding its range and is a nuisance, limestone is often near
the surface, and nesting sites are usually limited to sandy micro-
habitats along beaches or soil and mulch piles brought in from
the mainland for landscaping. Besides removing I. iguana from
the wild whenever possible, in areas where suitable nesting areas
are limited, we recommend establishing artificial nesting sites
and removing the eggs. Suitable nesting mounds using sand,
soil, or mulch can be placed in key problem areas for the express
purpose of luring female iguanas. Monitoring these sites during
the nesting season might help control the population, but care
must be taken to locate and remove all iguana eggs. An easier
solution than laboriously searching a mound of dirt for eggs
would be to construct a small artificial nest box that would con-
centrate iguana eggs. Werner and Miller (1984) designed a sim-
ple but successful nest box using six concrete blocks 40 x 20 x
10 cm (15 x 8 x 4 in) and two clay tubes 30 cm long x 20 cm
outside diameter (12 x 8 in). The interior of the nest chamber
is 40 cm long, 20 cm wide, and 10 cm high (15 x 8 x 4 in) and
filled with loose dirt. The 60-cm (24 in) long entrance tube,
which has a 15 cm (6 in) interior diameter, is one-third to half
Adult male Green Iguana (Iguana iguana) basking on a fallen tree dur-
ing a cool day at Crandon Park on Key Biscayne, Miami-Dade
County, Florida (photographic voucher UF 150121). Non-native
Senegal Date Palms (Phoenix reclinata) can be seen in the background.
KEVIN M. ENGE
filled with a 7-cm (2.75 in) layer of dirt; iguanas will fill this tube
while excavating the nest chamber, indicating that nesting
females or eggs are present and can be removed. This nest box
is set on the surface of the ground and covered with 3 cm (1 in)
of dirt; and the nest chamber is checked for eggs by removing
one or both of the concrete blocks that form the roof. In an arti-
ficial nesting chamber, Werner and Miller (1984) believed that
substrate composition is relatively unimportant (iguanas have
been observed nesting in different mixtures of soil and sand, and
even in ashes and refuse in garbage dumps), but solid walls and
a roof are essential. These artificial nest sites should be moni-
tored during the nesting season and all eggs or iguanas removed
before refilling the nest chambers with displaced dirt from the
entrance tubes. We recognize that this type of artificial nest box
cannot be moved easily once constructed. Thus, we suggest
using lighter-weight materials such as a similarly sized plastic,
rubber, or fiberglass shell (for the chamber) and PVC tube (for
the entrance), which will allow the nest box to be moved easily
to different sites. Furthermore, these artificial boxes can be used
to remove adult Green Iguanas as well as Spiny-tailed Iguanas
(Ctenosaura spp.), as both species utilize burrows throughout the
year. 14
Acknowledgements
We thank A. Nichole Hooper, Anthony T. Reppas, Todd S.
Campbell, Julian C. Lee, Andy P. Borgia, Rick Rego, Steve A.
Johnson, Kurt W. Larson, Esther M. Langan, Larry D. Wilson,
Sean B. Thompson, Debbie T. Townsend, Steve H. Townsend,
Bill Love, F. Wayne King, Chris S. Samuelson, Brooke L. Talley,
Kristen L. Bell, Brian J. Camposano, Lorraine P. Ketzler, David
G. Cook, Thomas M. Cravens, Ronald St. Pierre, George J.
Ward, and Mark A. Flowers for assistance in the field; Stan
Chrzanowski, Jim Duquesnel, Keith Laakkonen, Mike Owen,
Thomas Owen, Carl May, Jeffrey R. Schmid, and Anthony
Flanagan for providing photographs and information; Jim and
Janice Duquesnel, Bill Love, Chris Bergh, Dennis Giardina,
Nancy Richie, Raymond Goushaw, Ray Van Nostrand, Carl
May, Kenyatta K. Nichols, and J.H. Altman for information of
iguana populations in Florida; and Audrey K. Owens for illus-
trating the artificial iguana nest box.
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Appendix. Voucher specimens of Iguana iguana examined from Florida counties.
Alachua: UF 122514; Broward: UF 123126–27, 134066, 146556, 149568–69,
149979–81, 150124; Collier: UF 141486, 146036, 146067, 146273–74,
149612; Lee: UF 133209–10; Miami-Dade: ETMNH-CC 418–32; ISUVC
3846–47, 3849–53, 3855–92; UF 22910, 131544–47, 131556–60,
131764–66, 132864–83, 133838–41, 134203–10, 134231, 134910,
135083–91, 135093–94, 135294, 135470–71, 135485–89, 135494–500,
135538–63, 135616–22, 135624, 135896, 135907–23, 135925–46, 137405,
140562–65, 140579–82, 140740, 141040–41, 141098, 141101–03,
141109–19, 141220–23, 141225–27, 141230–31, 141233–34, 141236–39,
141248–49, 141487–96, 141498, 141609–17, 141766–68, 141897–99,
141902–03, 141953, 142317, 142333–42, 142344–54, 142551–74,
142591–95, 142625–80, 142722–24, 142731, 142812, 142817–19,
142897–904, 143602, 143605, 143607–08, 143946–48, 144060,
144239–41, 144261–65, 144268–97, 144310, 144312–23, 144343–471,
144575, 145202–14, 145218–333, 145335–57, 149715–32, 149734–810,
149873, 149892–978, 149982, 150002–13, 150121–23; USNM 245339;
YPM 13950–52; Monroe: UF 131549, 133862, 134836, 137214, 141212,
145524, 149864, 149985–86, 150065, 150093; Palm Beach: UF 137086,
137183, 146557–72, 149863, 149868–70, 150079.
... In captive collections, I. iguana has also been associated with bacterial skin infections, which raises biosecurity risks for native reptiles (Hellebuyck et al., 2018;Bautista-Trujillo et al., 2020). Socially and economically, the herbivorous diet of I. iguana can be problematic for gardeners and horticulturalists (Krysko et al., 2007;Falcón et al., 2013). Their burrowing behavior can cause soil erosion and bank destabilization, which can lead to damage to infrastructure (López-Torres et al., 2012). ...
... Our growing knowledge of threats posed by invasive I. iguana populations (e.g. Krysko et al., 2007;Falcón et al., 2013) highlights the urgent need to better understand the current status of these populations and implement control programs to address them. ...
... For example, the species was only scientifically verified on Andros Island, Bahamas, in September 2019, but the same study retrospectively established that local people had encountered I. iguana for at least three years prior (Johnson, 2020). As a further example, sightings of I. iguana were mostly sporadic in Florida during the 1960s (Krysko et al., 2007) and a population materialised over a period of a few decades, which is now difficult to control (Townsend et al., 2003). Based on these examples, it could be plausible that emerging reports of I. iguana in Hong Kong could represent a contemporary invasion presently under way. ...
... Although free-living individuals were first observed in Florida in the 1960s (King and Krakauer 1966), evidence of selfsustaining populations came only decades later (Meshaka et al. 2004). During the 1990s, populations in southern Florida expanded exponentially (Krysko et al. 2007), likely taking advantage of plentiful food and few predators (Townsend et al. 2003). Today, iguanas are found in most of Florida's coastal areas, reaching the highest densities in frost-free areas (Meshaka et al. 2004). ...
... Today, iguanas are found in most of Florida's coastal areas, reaching the highest densities in frost-free areas (Meshaka et al. 2004). In one case, 824 iguanas were removed from a state park in 2003, with no signs of a subsequent population decline (Krysko et al. 2007). Adults and hatchlings have been reported in Cameron County in southern Texas, but no breeding populations had been confirmed by 2004 (Meshaka et al. 2004). ...
... Despite the currently low number of reported Green Iguanas outside of Florida, surveillance for new observations in the USA is worthwhile. During the 1960s, iguana sightings in Florida were also sporadic and the present populations materialized progressively after two to three decades (Krysko et al. 2007) and are today difficult to control (Townsend et al. 2003;Meshaka et al. 2007). This highlights the importance of gathering information useful for wildlife managers to investigate early incursions and initiate pre-emptive interventions. ...
Article
Full-text available
Presently, the only established populations of invasive Green Iguanas (Iguana iguana) on the mainland USA occur in Florida. We examined observation data from the online citizen-science application iNaturalist to determine the frequency of reports of free-living Green Iguanas in Florida and identify where iguanas have been reported in other parts of the mainland USA. Observations from Florida comprised 99.6% of the 5,929 verified Green Iguana observations from the mainland USA. The largest proportion were observations from 2016 to 2021, corresponding with an increasing number of application users contributing to the dataset during this period. The majority of Green Iguana observations from latitudes of 27–41°N in 11 other mainland states were from California. However, we noted no obvious concentrations of sightings to indicate the presence of established populations in any of those 11 states. The majority of observations from outside Florida were adults and were most frequently reported from suburbia and urban parks, suggesting that released or escaped pets were the likely source. More than one third of iguanas reported outside Florida were near water, which is worrisome because iguanas are known to use waterways to disperse. This study clearly demonstrates the value of public participation in assembling sighting records of non-native animals, and we encourage engagement campaigns that leverage reports from members of the public to achieve early detections of potentially invasive species.
... In the last few decades, there have been reports of green iguanas becoming increasingly abundant in urban areas (Townsend et al. 2003). This is thought to be largely due to the popularity of green iguanas as pets, particularly in Florida, where they sometimes escape or are intentionally released by owners who find them difficult to care for (Townsend et al. 2003;Meshaka et al. 2004;Krysko et al. 2007). ...
... Populations of green iguanas occur in urban areas of southern mainland Florida and the Florida Keys (Meshaka et al. 2004), and it is thought that colder winter temperatures have limited their range and expansion further north (Townsend et al. 2003). It has been suggested that the numerous canal systems in Florida have facilitated the dispersal and colonization of iguanas in new areas (Meshaka et al. 2004;Krysko et al. 2007). ...
... In urban environments, they are typically found in areas with plenty of foliage, low numbers of potential predators (Campbell 2011), and nearby bodies of water such as bays, estuaries, canals, channels, ponds, and ditches (Meshaka et al. 2004;García-Quijano et al. 2011). In areas with little or no trees, such as vacant lots and cleared canal banks, they may also seek shelter in drainage pipes, culverts, burrows, and piles of rock or debris (Krysko et al. 2007). Green iguanas have been observed basking in many different urban and suburban areas, such as residential lawns, pavements, roads, park benches, airport runways, and golf courses (Townsend et al. 2003;Krysko et al. 2007;Gomez et al. 2020). ...
Technical Report
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The welfare of wild animals has so far received little attention in the scientific literature, particularly concerning wild animals living in urban environments. While there has been an increasing amount of research regarding urban wild animals over the last few decades, it has primarily been focused on the topics of animal behavior, conservation, landscape ecology, wild animal management, and population ecology. Few of these studies have considered the wellbeing of urban animals, but information from this research can be used to consider the ways in which urban wild animal welfare may be impacted. This review aims to gain a better understanding of what the lives of urban wild animals are like and the factors that may positively or negatively affect their welfare. This information can then be used to devise ways of improving overall welfare and reducing suffering in urban wild animals. We will also present ideas regarding future research that could inform the development of a new research field called urban welfare ecology. We conducted a review of publications on urban wild animals from various fields to investigate how the welfare of these animals may be impacted. Definitions of the term “urban” vary within the existing field of urban ecology, and we have specified the types of urban areas and degrees of urbanization as they have been described in the literature. We consider the general term “urban” to refer to areas occupied by humans that have a relatively high cover of buildings and infrastructure, primarily cities, suburbs, and industrial areas.
... In addition to thriving in human-modified areas in Florida (e.g., suburban neighborhoods), they also inhabit natural habitats such as mangroves and pinelands (8). They are common along canals and levees in southern Florida, and their ability to colonize such areas, which can act as corridors for dispersal, has likely contributed to their range expansion (15). ...
... At night they sleep in trees (if present), crevices in rocks, and burrows they dig. They will also shelter in drainage pipes, culverts, piles of debris, and similar hiding places created by people (15). They use their burrows and other underground refugia as hiding places when disturbed by people. ...
... The green iguana is largely herbivorous and eats a variety of plants. They prefer flowers, fruits, tender shoots, and many ornamental plants (15,16) but typically avoid citrus and thick-leaved plants (16). Hatchlings and juveniles eat insects in addition to vegetation (15). ...
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This is one in a series of similar EDIS documents summarizing general knowledge about Florida's introduced reptiles.
... Green Iguanas exploit a range of habitat strata from arboreal perches to aquatic habitats. The species' adaptability corresponds with a wide natural range throughout the Neotropics and subsequent invasions of some West Indian islands, Florida, Hawaii, Fiji, Japan, Taiwan, Singapore, and Thailand (McKeown 1996;Krysko et al. 2007;Falcón et al. 2012;van den Burg et al. 2020;De Jesús Villanueva et al. 2021). The anthropogenic spread of the Green Iguana is largely associated with their popularity as pets (Knapp et al. 2020). ...
... Green Iguanas are almost entirely herbivorous, with documented animal prey, mostly of juveniles, limited to terrestrial snails (Townsend et al. 2005), insects (Hirth 1963), bird eggs (Schwartz and Henderson 1991), and carrion (Loftin and Tyson 1965;Krysko et al. 2007). Despite their large size, adult Green Iguanas have numerous natural predators; these include wild cats (Chinchilla 1997;Loc-Barragán 2017), mustelids such as Tayras (Galef et al. 1976; Barrio-Amorós and Ojeda 2015) and otters (Pereira et al. 2020), coatis (Greene et al. 1978), snakes (Rivas et al. 2007;Ribeiro Sanches et al. 2018), crocodilians (Platt et al. 2006;Balaguera-Reina et al. 2018), and raptors (Greene et al. 1978), including owls (Filipiak et al. 2012). ...
... Moreover, hatchlings and juveniles are mobile organisms, and thus, in situ protection of these cohorts can only be done indirectly. Juveniles of diverse arboreal reptile species, unlike adults, use the understory to feed and to escape predators (Christian & Tracy, 1981;Henderson, 1974;Krysko et al., 2007). This habitat segregation may also lessen possible intraspecific competition for food and space with older cohorts (Henderson, 1974;Keren-Rotem et al., 2006;Stamps, 1983). ...
... ). Ovicide may be exacerbated when suitable nesting space, which in many iguana species is open area, bare ground, and deep, loose, well-drained soil, is limited(Krysko et al., 2007;Moss et al., 2020). For example, during a nesting survey of the Lesser Antillean iguana population of Dominica,Knapp et al. (2016) found that a minimum of 20% of eggs had been scattered outside of the nests and thus did not hatch.Soil erosion is severe on Chancel(Legouez et al., 2009). ...
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In long-lived species, although adult survival typically has the highest elasticity, temporal variations in less canalized demographic parameters are the main drivers of population dynamics. Targeting recruitment rates may thus be the most effective strategy to manage these species. We analyzed 1,136 capture–recapture histories collected over 9 years in an isolated population of the critically endangered Lesser Antillean iguana, using a robust design Pradel model to estimate adult survival and recruitment rates. From an adult population size estimated at 928 in 2013, we found a yearly decline of 4% over the 8-year period. As expected under the canalization hypothesis for a long-lived species, adult survival was high and constant, with little possibility for improvement, whereas the recruitment rate varied over time and likely drove the observed population decline. We then used a prospective perturbation analysis to explore whether managing the species’ immature cohorts would at least slow the population decline. The prospective perturbation analysis suggested that a significant and sustained conservation effort would be needed to achieve a recruitment rate high enough to slow the population decline. We posit that the high recruitment rate achieved in 2014—likely due to the maintenance in 2012 of the main nesting sites used by this population—would be sufficient to slow this population's decline if it was sustained each year. Based on the results of diverse pilot studies we conducted, we identified the most likely threats targeting the eggs and immature cohorts, stressing the need to improve reproductive success and survival of immature iguanas. The threats we identified are also involved in the decline of several reptile species, and species from other taxa such as ground-nesting birds. These findings on a little-studied taxon provide further evidence that focusing on the immature life stages of long-lived species can be key to their conservation.
... Green Iguanas are regionally naturalized due to their ubiquity across south Florida, negatively impacting native flora and fauna. For example, iguanas disperse invasive plants and are a destructive, nuisance species in human environments (Krysko et al. 2007); they contribute to the decline of endangered plants and invertebrates (e.g., from consuming host plants; Saarinen et al. 2014, Townsend et al. 2005. The invasion of these and other reptiles in the Florida Keys could negatively impact the various endangered endemic species occurring in the island chain (Lazell 1989). ...
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Florida is renowned for its non-native reptile communities, with 2 such pervasive non-native species including the apex predator Python bivittatus (Burmese Python) and the herbivorous Iguana iguana (Green Iguana) that showcase the spectrum of their ecological impacts. Both species have recently expanded into the Florida Keys. We used a camera trap to survey a radio-tagged Burmese Python and documented both non-native reptiles cohabitating in the active, natural stick-nest of an endangered rodent, Neotoma floridana smalli (Key Largo Woodrat), in Dagny Johnson Botanical State Park, Key Largo, FL. An additional nest visitor included Peromyscus gossypinus allapaticola (Key Largo Cotton Mouse), another endangered rodent and potential prey for the python. Camera placement allowed us to detect both rodents on the exterior of the stick-nest. The presence of the Key Largo Woodrat and Key Largo Cotton Mouse at the nest warrant continued monitoring of the 2 reptile species and their interactions with the endangered small mammals as their presence becomes more common in the Florida Keys.
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This datasheet on Iguana iguana covers Identity, Overview, Distribution, Dispersal, Hosts/Species Affected, Biology & Ecology, Natural Enemies, Impacts, Uses, Prevention/Control, Management, Further Information.
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Host association is among the most important factors that drive the transmission dynamics of mosquito-vectored pathogens. Competent vectors that feed exclusively upon non-competent hosts will not transmit pathogens, and highly competent hosts that are not bitten by competent vectors will not contribute to pathogen amplification. Therefore, characterizing the blood-feeding ecology of vector mosquitoes is critical to understanding how zoonotic pathogens amplify within ecosystems and spillover to humans and domesticated animals. In North America, mosquito species of the subgenus Culex are considered the most important vectors of zoonotic Flaviviruses, particularly West Nile virus (WNV), St. Louis encephalitis virus (SLEV), and western equine encephalitis virus. Many species of the Culex subgenus Culex are thought to feed predominantly upon birds and mammals, a behavior that facilitates the amplification and spillover of these zoonotic pathogens. Much of our understanding of the host associations of Culex vectors is based on research conducted in the 1960s and 1970s that used serological methods to infer host group(s). Here we reevaluate host associations of six Culex species from the southern US (Florida and Arizona) using DNA barcoding-based blood meal analysis. Our results demonstrate that reptiles, particularly lizards, constitute an important, and previously underappreciated, group of vertebrate hosts for several subgenus Culex mosquitoes. In Florida, >25% of Culex nigripalpus blood meals were derived from lizards (mainly Anolis spp.), and reptile host use generally increased from north to south with ~10%, ~25% and ~60% of Cx. nigripalpus blood meals derived from reptiles in northern, central, and southern Florida, respectively. In southern Arizona, lizards (mainly Sceloporus spp. and Urosaurus ornatus ) constituted 40-45% of blood meals of Culex tarsalis , Culex thriambus , and Culex stigmatosoma . Other species of the subgenus Culex , including Culex quinquefasciatus , were not found to feed upon reptiles at the same sites, suggesting host association variation within Culex subgenus Culex . Whether or not lizards contribute to or dilute amplification of zoonotic Flaviviruses depends upon host competency of the lizard species bitten for WNV and SLEV. To date, very few studies have evaluated host competence of lizards for these viruses, so their roles in transmission cycles of zoonotic Flaviviruses remains obscure.
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Reptiles are popular exotic pets and green iguanas (Iguana iguana) are amongst the top ten most popular reptiles. Here we describe a captive 8-year-old female green iguana that was referred for treatment of a non-healing, discharging lesion on the side of the body. The lesion was surgically excised and histopathological analysis revealed an epidermal proliferation of neoplastic keratinocytes, with focal infiltration through the basement membrane, into the underlying superficial dermis. Marked dysplastic changes, characterized by multifocal dyskeratosis and keratin pearl formation were also noted. A diagnosis of cutaneous squamous cell carcinoma (SCC) was made. Two years later, the iguana has shown no signs of recurrence. This is the first report of successful treatment of cutaneous SCC in a green iguana and contributes to the limited knowledge of cutaneous neoplasms in green iguanas.
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Ten species of birds in 7 families were observed feeding upon Anolis lizards. No avian species consumed only anoles. Raptors and large insectivorous birds are most likely to prey upon anoles. Comparison of the proportion of anoles versus insects in the diets of mangrove cuckoos (Coccyzus minor), smooth-billed anis (Crotophagus ani), and carib grackles (Quiscalus lugubris) indicates that avian predation upon anoles is more intense during the dry season than during the wet season. -from Author
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The first herpetological collections from the Cayman Islands were made in Grand Cayman by W.B. Richardson and in Cayman Brac and Little Cayman by C.J. Maynard. These were described in several papers by Garman (1887a,b, 1888). Later, English (1912), Barbour and Noble (1916), Cochran (1934), Battersby (1938) and Sackett (1940) reported additional taxa. These papers were summarized by Grant (1940) in his extensive monograph published by the Institute of Jamaica. In a companion paper, listed as an Appendix in Grant’s compendium, Lewis provided a detailed historical account of the Cayman Island marine turtle fisheries (Lewis 1940).