The Earliest Horse Harnessing and Milking

Abstract

Horse domestication revolutionized transport, communications, and warfare in prehistory, yet the identification of early domestication
processes has been problematic. Here, we present three independent lines of evidence demonstrating domestication in the Eneolithic
Botai Culture of Kazakhstan, dating to about 3500 B.C.E. Metrical analysis of horse metacarpals shows that Botai horses resemble
Bronze Age domestic horses rather than Paleolithic wild horses from the same region. Pathological characteristics indicate
that some Botai horses were bridled, perhaps ridden. Organic residue analysis, using δ13C and δD values of fatty acids, reveals processing of mare's milk and carcass products in ceramics, indicating a developed
domestic economy encompassing secondary products.

Full text

pure imaginary as in Eq. 1. Calculation of f
ab
for
the L
2
edge using Eq. 5 gives
fab ¼
ðc1þic3Þðc∗
1−ic∗
3Þðic∗
1þc∗
3Þðc1−c2Þ0
ð−ic1þc3Þðc∗
1−c∗
2Þðc1−c2Þðc∗
1−c∗
2Þ0
00ðc2þic3Þðc∗
2−ic∗
3Þ
0
@1
A
ð4Þ
Because the magnetic signal comes from the
imaginary part of off-diagonal elements (12), the
necessary condition for the vanishing intensity is
c1¼c2or c3¼ic1ð5Þ
This condition places very stringent constraints on
the allowed hole state and rules out all single-
orbital S= 1/2 models. For the S= 1/2 case, the
imaginary part of the off-diagonal elements does
not vanish and equal resonant intensities are
expected at the L
2
and L
3
edges (Fig. 2B). Given
the constraints in Eq. 5, the scattering intensities at
L
3
edge are calculated to be
IL3¼1
4ðImðc1c∗
3ÞÞ2or
IL3¼1
4ðReðc∗
1c2ÞÞ2ð6Þ
respectively. Thus, taking the phase convention
c
1
= 1 without loss of generality, the resonant
intensity at L
3
measures the imaginary part of c
3
relative to the real part of c
2
, which is also a
measure of orbital angular momentum. The large
enhancement at L
3
necessarily implies that the yz
orbital is out of phase with the zx orbital, the
contrast between L
3
and L
2
being maximal when
the relative phase is p/2. Taking the constraints of
Eqs. 5 and 6 together, we conclude that the ground
state is very close to the J
eff
=1/2limit(c
1
:c
2
:c
3
=
1:1:i), and the minute enhancement at L
2
edge
shows the smallness of the deviation from the J
eff
=
1/2 limit coming from the factors not taken into
account (13).ThewavefunctioninEq.2,repre-
senting J
eff
= 1/2, indeed gives zero off-diagonal
elements in f
ab
for L
2
and nonzero elements for the
L
3
edge. This is a direct measurement of phase and
provides evidence for the J
eff
=1/2stateinSr
2
IrO
4
.
Having identified the nature of the local mo-
ment, we now look at the global magnetic structure
using the enhanced signal due to the resonance at
the L
3
edge. Sr
2
IrO
4
shows a metamagnetic tran-
sition below 240 K and, above the metamagnetic
critical field H
C
(≈0.2 Twell below 240 K), shows
weak ferromagnetism with a saturation moment of
≈0.1 m
B
/Ir (4). The origin of this field-induced
weak ferromagnetism has remained unidentified,
because the neutron diffraction data did not show
any detectable indication of magnetic ordering
(14). Our RXS results indicate that the magnetic
structure of Sr
2
IrO
4
is canted antiferromagnetic.
Figure 3A shows the crystal structure con-
taining four IrO
2
layers in a unit cell, enlarged by
superstructure from the rotational distortion of
octahedra (14). Figure 3B shows the magnetic
ordering pattern determined from the experiment
shown in Fig. 3, C to E. The arrows in Fig. 3B
do not represent spins but J
eff
=1/2moments.In
zero field, the magnetic reflections are observed
at (1 0 4n+2) and (0 1 4n), which implies that the
moments are aligned antiferromagnetically
within a layer and the symmetry changes from
tetragonal to orthorhombic (Fig. 3C). The canting
of the moments yields a nonzero net moment
within a layer, which orders in the up-down-down-
up antiferromagnetic pattern along the caxis. This
is evidenced by the presence of (0 0 odd)peaks
shown (Fig. 3D). The width of the peak gives an
estimate of interlayer correlation length of 100 c
or 400 IrO
2
layers. When the magnetic field
greater than H
C
is applied, the peaks at (1 0 4n+2)
disappear and new peaks show up at (1 0 odd)
(Fig. 3E), which implies that the net moments in
the planes are aligned ferromagnetically to produce
a macroscopic field. The temperature dependence
of the scattering intensity in the weakly ferro-
magnetic state above H
C
,showninFig.3F,scales
very well with that of the magnetization and
confirms again the magnetic nature of the peaks.
Our study demonstrates that x-rays can be ex-
tended to a new level to probe even finer details of
magnetic structure. Until now, only the intersite
interference effects were used to study ordering
phenomena over a length scale of many lattice
sites. A quantitative analysis on the interference ef-
fects within a single site provides phase information
on the constituent wave function of the electron
responsible for the magnetism. This technique
should find important applications in systems
where complex phases give rise to novel physics.
References and Notes
1. J. G. Bednorz, K. A. Muller, Z. Phys. B 64, 189 (1986).
2. For a review, see Colossal Magnetoresistive Oxides,
Y. Tokura, Ed. (Gordon & Breach Science, New York, 2000).
3. G. Cao, J. Bolivar, S. McCall, J. E. Crow, R. P. Guertin,
Phys. Rev. B 57, R11039 (1998).
4. Materials and methods are available as supporting
material on Science Online.
5. B. J. Kim et al., Phys. Rev. Lett. 101, 076402 (2008).
6. The parallel spin and orbital configuration are in
accordance with Hund's third rule in the case of more
than half-filled shell, despite its apparent contradiction
implied by the J
eff
= 1/2 quantum number [see (5)].
7. This results in an orbital moment twice as large as that of
spin,: < L
z
> = 2/3 and 2 < S
z
> = 1/3, with < L
z
>+2
<S
z
>=1.
8. A. Shitade, H. Katsura, X.-L. Qi, S.-C. Zhang, N. Nagaosa,
http://arxiv.org/abs/0809.1317.
9. G. Jackeli, G. Khaliullin, http://arxiv.org/abs/0809.4658.
10. Y. Murakami et al., Phys. Rev. Lett. 81, 582 (1998).
11. P. Abbamonte et al., Science 297, 581 (2002).
12. M. Blume, Resonant Anomalous X-ray Scattering, Theory
and Applications (Elsevier Science, Amsterdam, 1994).
13. The small enhancement at L
2
can be explained by finite
10Dq, which results in a small admixture of xy and x
2
–y
2
and small tetragonal splitting. It is not a priori obvious that
J
eff
= 1/2 can be stabilized in the presence of the tetragonal
crystal field, but the rotational distortion (Fig. 3A) acts in
the opposite direction to lower the xy state, and this delicate
balance may result in the J
eff
=1/2state(15).
14. M. K. Crawford et al., Phys. Rev. B 49, 9198 (1994).
15. B. J. Kim et al., Phys. Rev. Lett. 97, 106401 (2006).
16. The authors gratefully acknowledge discussions with
C. Kim, J.-H. Park, S. Fujiyama, J. Matsuno, B. Smith, and
G. Khaliullin; preliminary x-ray analysis by D. Hashizume;
and continuous encouragement by M. Takata and
T. Ishikawa. This work was partly supported by a Ministry
of Education, Culture, Sports, Science and Technology
(MEXT) Grant-in-Aid for Scientific Research (S)
(19104008) and Grant-in-Aid for Scientific Research on
Priority Areas ”Novel States of Matter Induced by
Frustration”(19052001 and 19052008).
Supporting Online Material
www.sciencemag.org/cgi/content/full/323/5919/1329/DC1
Materials and Methods
Figs. S1 and S2
References
13 October 2008; accepted 16 January 2009
10.1126/science.1167106
The Earliest Horse Harnessing
and Milking
Alan K. Outram,
1
*Natalie A. Stear,
2
Robin Bendrey,
3,7
Sandra Olsen,
4
Alexei Kasparov,
1,5
Victor Zaibert,
6
Nick Thorpe,
7
Richard P. Evershed
2
Horse domestication revolutionized transport, communications, and warfare in prehistory, yet the
identification of early domestication processes has been problematic. Here, we present three
independent lines of evidence demonstrating domestication in the Eneolithic Botai Culture of
Kazakhstan, dating to about 3500 B.C.E. Metrical analysis of horse metacarpals shows that Botai
horses resemble Bronze Age domestic horses rather than Paleolithic wild horses from the same
region. Pathological characteristics indicate that some Botai horses were bridled, perhaps ridden.
Organic residue analysis, using d
13
C and dD values of fatty acids, reveals processing of mare’s milk
and carcass products in ceramics, indicating a developed domestic economy encompassing
secondary products.
The domestication of the horse is associated
with the spread of Indo-European languages
and culture, bronze metallurgy, and special-
ized forms of warfare (1–3). Genetic studies of
modern domestic horse breeds (Equus caballus)
(4,5) imply either multiple domestication events
or domestic stallions from a single original
lineage being bred with captured local juvenile
wild mares (6,7), but fail to clearly identify when
and where horse domestication first took place. A
prime candidate for this locus is the Eurasian
steppe, specifically the Botai culture, northern
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Kazakhstan, in the mid–fourth millennium B.C.E.,
where faunal assemblages consist almost entirely
of horse remains (1,6–9). The case for horse
herding within the Botai culture includes a semi-
sedentary settlement structure, incompatible with
hunting mobile wild herds, and skeletal element
abundances lacking differential transport patterns
associated with large quarries. Tools that were
probably used for hide working and producing
leather straps predominate over projectile points
and other hunting equipment. However, age struc-
tures within horse herds at Botai do not clearly
indicate a husbanded rather than hunted popula-
tion (6,7,9,10). Indirect evidence for domesti-
cated horses is strongly suggestive but inconclusive.
Here, we discuss three new lines of direct evi-
dence to confirm early domestication of horses in
the Botai culture.
Horse metapodia are useful in archaeozoo-
logical metrical analyses because of their load-
bearing function and proclivity to undergo
morphological changes relating to breed and dif-
fering physical activities. Specimens were selected
from four sites in northern/central Kazakhstan,
including Botai (during the 2005–2006 seasons)
(11); the Tersek culture sites of Kozhai and
Kumkeshu [supporting online material (SOM)]
(12); and the large settlement of Kent (13),
dating to the late Bronze Age (circa 1300 to 900
B.C.E.), by which time the horses are clearly
domestic. Twelve key measurements were taken
(14), and principal components analysis (PCA)
revealed patterning between sites, with the load-
ing plot indicating that most differentiation related
to the ratio of greatest length (GL) against four key
width measurements. The ratios between GL and
greatest breadth of proximal epiphysis (Bp), small-
est width of diaphysis (SD), smallest depth of
diaphysis (SDD), and greatest breadth of distal
epiphysis (Bd) are indices of general limb slen-
derness, rather than overall size, and have been
used in differentiating equid species (15). All four
ratios show exactly the same pattern. Specimens
from the two Tersek sites, Kozhai and Kumkeshu,
show considerable similarity, whereas the domes-
tic horses from Kent are appreciably more slender.
The Botai horses are also significantly more slen-
der than those of the Tersek sites, with the dis-
tribution of ratios at Kent and Botai being very
similar (no significant difference at 95% confi-
dence interval in a Student’sttest of difference
between means of the four ratios). However, the
Botai specimens showed significant differences in
the means of the SD/GL, SDD/GL, and Bd/GL
ratios of Kumkeshu and Kozhai at high confi-
dence levels (well above 95%), whereas the
Bp/GL test fell just short of a 90% confidence
level. Figure 1 shows a scatter plot of two of the
mean ratios (SD/GL and Bd/GL) for the sites
discussed above and two other published pop-
ulations: Kuznetsk (16) late Pleistocene horses
(deriving from Palaeolithic sites in Novokuznetsk,
southern Siberia; being the geographically closest
wild horses for which the appropriate measure-
ments are available) and modern Mongolian do-
mestic horses (17). The Botai horses cluster very
closely with the Bronze Age domestic horses from
Kent and modern Mongolian domestic horses.
The Kuznetsk Paleolithic horses appear to be
much less slender, and the Tersek population
displays intermediate morphology. The domestic
populations are clearly more slender and, most
significantly, the Botai horses plot with the
modern Mongolian and Bronze Age domestic
specimens, providing evidence that the Botai
horses were domesticated.
We examined evidence for bitting damage
resulting from harnessing with a bridle or similar
restraint (this may refer to a range of possible
mouthpieces, including leather thong bridles), in
which damage to the skeletal tissues of the mouth
occurs when a horse is ridden or driven with a
bit/bridle. A macroscopic method that quantifies
bitting damage to the mesial or anterior edge of
mandibular second premolars (P
2
s) was applied
(18). When a horse is bitted, the bit is placed in
the mouth on the mandibular diastema (the
bridge of bone between the anterior and cheek
teeth), where it can come into contact with the
mesial edge of P
2
s and cause a recognizable
vertical strip of wear through the cementum to
expose the enamel. More severe wear exposes
dentine below the enamel. However, not all
enamel exposure on the anterior border of P
2
sis
1
Department of Archaeology, University of Exeter, Exeter, EX4
4QE, UK.
2
School of Chemistry, University of Bristol, Bristol,
BS8 1TS, UK.
3
CNRS UNR 5197, Muséum Nationale d’Histoire
Naturelle, Paris 75005, France.
4
Carnegie Museum of Natural
History, Pittsburgh, PA 15206–3706, USA.
5
Institute for the
History of Material Culture, RAS, St. Petersburg 191186,
Russia.
6
Kokshetau University, 020000 Kokshetau, Akmolinsk
Oblast, Kazakhstan.
7
Department of Archaeology, University of
Winchester, Winchester SO22 4NR, UK.
*To whom correspondence should be addressed. E-mail:
a.k.outram@ex.ac.uk
0.140 0.150
0.210
0.220
0.230
0.1700.160
DOMESTIC
WILD
Kent n = 36
Botai n = 18
Kozhai n = 12
Kuznetsk n = 34
Bd/GL
SD/GL
Mongolian
Mongolian
n = 4
n = 4
Mongolian n = 4
Kumkeshu
Kumkeshu
n = 41
n = 41
Kumkeshu n = 41
Fig. 1. Scatter plot of mean ratios of measurements Bd/GL and SD/GL on horse metacarpals from
different ancient and modern populations. Botai horses plot in association with other ancient and
modern domestic populations. Bars are mean Tinterquartile ranges (not available from published
data for Kuznetsk or Mongolian populations).
Fig. 2. A Botai stallion’s lower second premolar
(mesial edge), displaying a clear parallel-sided
band of bit wear that penetrates through the
cementum and enamel. This morphology and
depth of wear occur only in bridled animals
[figures 2 and 4 of (18)].
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due to bitting, and other forms of damage can
occur, such as dietary wear, so interpretations
must consider the size and shape of the area
exposed. The bit also comes into contact with the
upper surface of the diastema, which can lead to
periostitis at this site (19), and repetitive contact
can result in the deposition of pathological new
bone or destruction of bone (18). The criteria
used in this investigation are based on studies of
modern animals (bitted and unbitted) with known
life histories (18). From the 2005–2006 Botai
excavations, 15 P
2
s (table S1) displaying full
occlusal wear (that is, in excess of 4 years old)
and mandibular diastemata were examined. Of
nine measurable P
2
s, specimen no. 7 exhibited
changes to the anterior edge that could be un-
ambiguously attributed to bitting damage, as
evidenced by wear that penetrated through the
enamel to expose the dentine (Fig. 2). Mamma-
lian tooth enamel is very hard (about 300 to 400
Vickers hardness number), and although enamel
exposure occurs in both bitted and unbitted
equids (cementum can also be removed through
dietary wear), dentine exposure in this area
occurs only in bitted/bridled animals (18). Two
further P
2
s exhibited bands of enamel exposure
that were possibly caused by bit wear, but the
form of this is not a clear parallel-sided band, so it
is not unequivocal. Application of the mandibu-
lar diastema scoring system (18) identified four
cases of new bone formation at a level indicating
bitting/bridling. The clearly bitted P
2
(no. 7) was
dated by accelerator mass spectrometry to 4658 T
33 years before the present (3521 to 3363 calen-
dar years B.C.E., 94.6% probability; Oxford Radio-
carbon Accelerator Unit reference OxA-18383),
which is consistent with the Botai culture. Thus,
5 out of 15 mandibles studied provided evidence
of bitting damage.
The traditional economies of modern Kazakhstan
exploit horses for both meat and milk. Degraded
animal fat survives in archaeological pottery (20),
-28-32-34 -30 -26 -22
-22
-24
-26
-24
-28
-32
-30
-36
-34
-50
-150
-350
-250
-350 -150-300 -250 -200
Porcine adipose fat
Ruminant dairy fat
Ruminant
adipose fat
Equine adipose fat
Equine adipose fat
Equine adipose fat
Equine
adipose
Equine milk fat
Equine milk
Freshwater fish
adipose fat
Porcine adipose fat
Ruminant dairy fat
Freshwater fish
adipose fat
Ruminant
adipose fat
Equine adipose fat
Equine adipose fat
Equine adipose fat
Equine milk fat
Equine milk fat
Equine milk fat
Equine adipose
Equine milk
Milk
-36 -28
-32
-34 -30 -26 -22
-22
-24
-26
-24
-28
-32
-30
-36
-34
-50
-150
-350
-250
-350 -150-300 -250 -200
δD C16:0 δD C16:0
δD C18:0
δ13C18:0
δ13C18:0 (‰)
δ13C16:0 (‰) δ13C16:0
δD C18:0
A
B
C
D
Fig. 3. Scatter plots of d
13
CanddDvaluesoftheC
18:0
and C
16:0
fatty acid animal
fats of modern reference fats (Aand B, respectively) and of organic residues from
archaeological potsherds (Cand D, respectively) from Kazakhstan. (C) shows the
d
13
CvaluesofC
18:0
and C
16:0
fatty acids of 50 analyzable lipid residues from 89
Botai potsherds sampled, and (D) shows the dDvaluesoftheC
18:0
and C
16:0
fatty
acids of the residues from potsherds assigned as equine fats. All confidence ellipses
are mean TSD and correspond to the values exhibited by modern reference fats.
The residues highlighted in red correspond to archaeological equine milk fats.
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and its sources can be classified on the basis of
the d
13
C values of the major n-alkanoic acids,
palmitic (C
16:0
) and stearic (C
18:0
) acid, which
allows nonruminant and ruminant carcass and
ruminant dairy fats to be distinguished (21,22).
Ruminant dairying developed relatively quickly
after the domestication of cattle, sheep, and goats
(23); direct identification of mares’milk in pot-
tery vessels would be clear evidence of horse
domestication. Sampling of modern animal fats, in-
cluding equine adipose and milk fats from Kazakh
animals fed on the natural steppe vegetation, was
undertaken. Although horse adipose and milk
fats were resolved from the fats of ruminant
animals, their d
13
C values overlap (Fig. 3A);
hence, although equine fats can be detected with
this approach, equine milk cannot be unambigu-
ously identified.
To achieve separation, we used compound-
specific deuterium isotope (dD) analysis of the
major n-alkanoic acids, exploiting the phenome-
non that in midcontinental regions, such as the
Eurasian steppe, the dD values of summer and
winterprecipitationconsistentlydifferby>100per
mil (24). Tissue lipid integrates both the water and
dietary deuterium signal (25), hence their adipose
fat integrates the annual dD signal. However,
summer milk fat records only the summer dD
signal; thus, the dD values of fatty acids in sum-
mer milk and adipose fats will differ because of
the large difference in the dDvaluesofsummer
versus mean annual precipitation. Figure 3B con-
firms that the dD values of the modern reference
horse fats exhibit the predicted difference between
adipose and summer milk fats.
The d
13
C values from the major fatty acid
components of the Botai cooking vessels confirm
the preponderance of horse fat residues (Fig. 3C),
mirroring the dominance of horse bones at the
site. A few residues fall into the ruminant refer-
ence distribution, which may well indicate the
presence of small numbers of hunted cervids or
bovids. Most significantly, the dD values show
two distinct clusters. The red points in Fig. 3, C
and D, correspond to the respective d
13
CanddD
values of the same five potsherds. All the dD
values of the fatty acid components of these
residues exhibit significantly elevated dDvalues.
They very likely derive from mare’s milk because
of their relative displacement from the major
cluster of carcass fats (Fig. 3D and SOM). The
relatively higher dD values in the archaeological
fats are consistent with increased aridity during
this period of prehistory (26,27).
Although existing archaeological evidence
for horse domestication at Botai is inconclusive
(10), our new skeletal evidence, based on meta-
carpal metrics, supports the presence of a propor-
tion of domesticated horses in the Botai herds.
Moreover, our bitting damage evidence indicates
the use of bridles to control working animals and
supports assertions that finds of leather thong–
producing tools are consistent with horse domes-
tication (6,7). Finally, evidence for extensive
horse carcass product processing in pottery
vessels provides direct evidence for their exploi-
tation as a dietary staple. The demonstration of
mares’milk processing confirms that at least
some of the mares at Botai were domesticated.
The fact that horse milking existed in a region
remote from the locus of ruminant domestication
in the “Fertile Crescent”and in an area seemingly
devoid of domestic ruminants indicates that the
evolution of strategies for exploiting animals for
their milk was not contingent on the adoption of
the conventional “agricultural package,”as it
appears to have developed independently in the
Botai region.
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Supporting Online Material
www.sciencemag.org/cgi/content/full/323/5919/1332/DC1
SOM Text
Table S1
References
17 November 2008; accepted 14 January 2009
10.1126/science.1168594
Promoting Intellectual Discovery:
Patents Versus Markets
Debrah Meloso,
1
*Jernej Copic,
2
Peter Bossaerts
3
Because they provide exclusive property rights, patents are generally considered to be an
effective way to promote intellectual discovery. Here, we propose a different compensation scheme,
in which everyone holds shares in the components of potential discoveries and can trade those
shares in an anonymous market. In it, incentives to invent are indirect, through changes in share
prices. In a series of experiments, we used the knapsack problem (in which participants have to
determine the most valuable subset of objects that can fit in a knapsack of fixed volume) as a
typical representation of intellectual discovery problems. We found that our “markets system”
performed better than the patent system.
In a patenting system, the first to discover the
solution to a problem receives a prize in the
form of exclusive property rights to the fruits
from the discovery. Patents are generally viewed as
a superior way to promote intellectual discovery
because they provide strong incentives to invest in
effort, the cost of which can be recuperated from the
earnings generated by applications of the discovery.
The patent system has been criticized on
various grounds. First, there is the obvious fair-
www.sciencemag.org SCIENCE VOL 323 6 MARCH 2009 1335
REPORTS
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The Earliest Horse Harnessing and Milking
Evershed
Alan K. Outram, Natalie A. Stear, Robin Bendrey, Sandra Olsen, Alexei Kasparov, Victor Zaibert, Nick Thorpe and Richard P.
DOI: 10.1126/science.1168594
(5919), 1332-1335.323Science
ARTICLE TOOLS http://science.sciencemag.org/content/323/5919/1332
MATERIALS
SUPPLEMENTARY http://science.sciencemag.org/content/suppl/2009/03/04/323.5919.1332.DC1
REFERENCES http://science.sciencemag.org/content/323/5919/1332#BIBL
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