| Far back in the
Tertiary Period, over 50 million years ago, there evolved a group of small,
early carnivores known as the Miacidae. Like many other modern mammalian
groups, these animals evolved from primitive insectivores which had lived
alongside the dinosaurs during the Cretaceous Period. Many paleontologists
strongly believe that the miacids are the most likely ancestors of the
Canidae, which includes all wolves, dogs, and foxes. As I stated
in this section's introduction page, the genus Canis itself is a
rather recent development. Some species of this genus, such as the
modern grey wolf, have only come about in the past one million years.
Other canids, such as foxes, are older by comparison. The grey fox,
Urocyon cinereogenteus is widely considered to be the most primitive
canid alive today.
Grey wolves (Canis lupus) most likely
originated in Asia. It probably took up residence in North America
some 700,000 years ago, after having crossed the Pleistocene land bridge
which connected the two continents at that time. The dire wolf, Canis
dirus, a somewhat larger and more robust form of wolf, had evolved
in North America earlier. The dire wolf and grey wolf shared the
continent for nearly half a million years, until the dire wolf, along with
many other large Pleistocene species, died out in the great extinction
of 16,000 years ago.
The place of the red wolf (Canis rufus)
in the history of wolves is not yet very clear. Some believe that
it is not a true species at all, but instead the product of hybridization
between grey wolves and coyotes. Others theorize that it is a true
species unique to North America which once had a much wider distribution
than it does today, but retreated to the southeastern portion of the country
as the grey wolf advanced farther south. Alternatively, the red wolf
could also merely be an variety of Pleistocene wolf which became
geographically isolated from other populations, and now has a very confined
range. For the purposes of conservation and taxonomy, the most popular
view is that the red wolf does merit species status. However,
most red wolves alive today, even those considered as "pure", almost certainly
have at least some coyote ancestry. The red wolf gene pool was in
recent history flooded with coyote influence because of the difficulty
red wolves encountered in finding mates of their own kind. This occurred
because man had killed so many of the "true" red wolves, and coyotes were
much better able to survive extermination efforts. If hybridization
with coyotes had not occurred, all trace of the red wolf may have been
lost completely, as the number of red wolves became so dangerously low. |
