One point I often come back to is how the Pleistocene fauna is in many ways so similar to today’s fauna. Geologically speaking, the Ice Age is the recent past; many of the species alive then are still with us today.
The bone shown above is the right metacarpal (forefoot bone) of a deer from the genus Odocoileus. Odocoileus is the most common large wild mammal in North America today, with the white-tailed deer O. virginianus found through most of the continent and into South America, and the mule deer O. hemionus ranging throughout western North America. While mule deer tend to be a bit larger than white-tailed deer (at least today), it’s difficult if not impossible to distinguish between them based on limited remains such as this.
This metacarpal is incomplete, with the proximal portion (closest to the wrist) broken off. The image above is in anterior view, while below is the posterior view:
At the distal end of the bone, note that there are two articulations. Deer are members of the Family Cervidae, which are in the Order Artiodactyla. Like their relatives the Bovidae (cattle and their kin), Camelidae (camels), and many other artiodactyl groups, deer have two digits on each foot, digits III and IV (the middle and ring fingers on the hand, and the equivalent toes on the foot).
Deer were not a major component of the fossil fauna at Diamond Valley Lake; horses, bison, camels and even mastodons are more common as fossils in these deposits. Nevertheless, they were common enough for multiple specimens to show up in the sample.