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Statement for the 109th Congress (1st Session)
in support of H.R. 297
A BILL IN THE HOUSE OF REPRESENTATIVES
House Committee on
Resources
Introduced January 25,
2005
To restore the prohibition
on the commercial sale and slaughter of wild free-roaming horses and
burros.
Wild
Horses as Native North American Wildlife
By Jay
F. Kirkpatrick, Ph.D. and Patricia M. Fazio, Ph.D.*
Are
wild horses truly “wild,” as an indigenous species in North America,
or are they “feral” weeds – barnyard escapees, far removed genetically
from their prehistoric ancestors? The question at hand is, therefore,
whether or not modern horses, Equus caballus, should be
considered native wildlife.
The
genus Equus, which includes modern horses, zebras, and asses,
is the only surviving genus in a once diverse family of horses that
included 27 genera. The precise date of origin for the genus
Equus is unknown, but evidence documents the dispersal of Equus
from North America to Eurasia approximately 2-3 million years ago and
a possible origin at about 3.4-3.9 million years ago. Following this
original emigration, several extinctions occurred in North America,
with additional migrations to Asia (presumably across the Bering Land
Bridge), and return migrations back to North America, over time. The
last North American extinction occurred between 13,000 and 11,000
years ago.
Had it not been for previous westward migration, over the land bridge,
into northwestern Russia (Siberia) and Asia, the horse would have
faced complete extinction. However, Equus survived and spread
to all continents of the globe, except Australia and Antarctica.
In
1493, on Columbus’ second voyage to the Americas, Spanish horses,
representing E. caballus, were brought back to North America,
first in the Virgin Islands, and, in 1519, they were reintroduced on
the continent, in modern-day
Mexico,
from where they radiated throughout the American Great Plains, after
escape from their owners.
Critics
of the idea that the North American wild horse is a native animal,
using only paleontological data, assert that the species, E.
caballus (or the caballoid horse), which was introduced in 1519,
was a different species from that which disappeared 13,000 to 11,000
years before. Herein lies the crux of the debate. However, the
relatively new (27-year-old) field of molecular biology, using
mitochondrial-DNA analysis, has recently found that the modern or
caballine horse, E. caballus, is genetically equivalent to
E. lambei, a horse, according to fossil records, that represented
the most recent Equus species in North America prior to
extinction. Not only is E. caballus genetically equivalent to
E. lambei, but no evidence exists for the origin of E.
caballus anywhere except North America.
According to the work of Uppsala University researcher Ann Forstén, of
the Department of Evolutionary Biology, the date of origin, based on
mutation rates for mitochondrial-DNA, for E. caballus, is set
at approximately 1.7 million years ago in North America. Now the
debate becomes one of whether the older paleontological fossil data or
the modern molecular biology data more accurately provide a picture of
horse evolution. The older taxonomic methodologies looked at physical
form for classifying animals and plants, relying on visual
observations of physical characteristics. While earlier taxonomists
tried to deal with the subjectivity of choosing characters they felt
would adequately describe, and thus group, genera and species, these
observations were lacking in precision.
Reclassifications are now taking place, based on the power and
objectivity of molecular biology. If one considers primate evolution,
for example, the molecular biologists have provided us with a
completely different evolutionary pathway for humans, and they have
described entirely different relationships with other primates. None
of this would have been possible prior to the methodologies now
available through mitochondrial-DNA analysis.
Carles
Vilà, also of the Department of Evolutionary Biology at Uppsala
University, has corroborated Forstén’s work. Vilà et al have
shown that the origin of domestic horse lineages was extremely
widespread, over time and geography, and supports the existence of the
caballoid horse in North American before its disappearance.
Finally, the work of Hofreiter et al,
examining the genetics of the so-called E. lambei from the
permafrost of Alaska, found that the variation was within that of
modern horses, which translates into E. lambei actually being
E. caballus, genetically. The molecular biology evidence is
incontrovertible and indisputable.
The
fact that horses were domesticated before they were reintroduced
matters little from a biological viewpoint. They are the same species
that originated here, and whether or not they were domesticated is
quite irrelevant. Domestication altered little biology, and we can see
that in the phenomenon called “going wild,” where wild horses revert
to ancient behavioral patterns. James Dean Feist dubbed this “social
conservation” in his paper on behavior patterns and communication in
the Pryor Mountain wild horses. The reemergence of primitive
behaviors, resembling those of the plains zebra, indicated to him the
shallowness of domestication in horses.
The issue of feralization
and the use of the word “feral” is a human construct that has little
biological meaning except in transitory behavior, usually forced on
the animal in some manner. Consider this parallel. E. Przewalski
(Mongolian wild horse) disappeared from Mongolia a hundred years
ago. It has survived since then in zoos. That is not domestication in
the classic sense, but it is captivity, with keepers providing food
and veterinarians providing health care. Then they were released a few
years back and now repopulate their native range in Mongolia. Are they
a reintroduced native species or not?
And what is the
difference between them and E. caballus in North America,
except for the time frame and degree of captivity?
The key element in
describing an animal as a native species is (1) where it originated;
and (2) whether or not it co-evolved with its habitat. Clearly, E.
caballus did both, here in North American. There might be
arguments about “breeds,” but there are no scientific grounds for
arguments about “species.”
The non-native, feral,
and exotic designations given by agencies are not merely reflections
of their failure to understand modern science, but also a reflection
of their desire to preserve old ways of thinking to keep alive the
conflict between a species (wild horses) with no economic value
anymore (by law) and the economic value of commercial livestock.
Native status for wild horses would place these
animals, under law, within a new category for management
considerations. As a form of wildlife, embedded with wildness, ancient
behavioral patterns, and the morphology and biology of a sensitive
prey species, they may finally be released from the
“livestock-gone-loose” appellation.
_________________________________
Jay F. Kirkpatrick, Director, The Science and
Conservation Center, Billings, Montana, holds a Ph.D. in reproductive
physiology from the College of Veterinary Medicine at Cornell
University. Patricia M. Fazio is currently a freelance environmental
writer and editor residing in Cody, Wyoming and holds a B.S. in animal
husbandry/biology from Cornell University, an M.S. in environmental
history from the University of Wyoming, and a Ph.D. in environmental
history from Texas A&M University, College Station.
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(Distributed March 2, 2005)
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Ω
Please note:
This document is the sole intellectual property of
Drs. Jay F. Kirkpatrick and Patricia M. Fazio. As such, altering of
content in any manner is strictly prohibited. However, this
statement may be copied and distributed freely in hardcopy,
electronic, or Website form (March 2, 2005).
(03/2/05) |
