Fossilized Horse

One of North America's most incredible mammal fossils ever discovered, this fossil is the most complete "dawn horse" (Protorohippus venticolus) currently on record; it is one of only two horse skeletons discovered in Wyoming's Green River Formation. The five fish embedded in the slab are a testament to the rare circumstances that led to this land animal being buried in the middle of Fossil Lake. The details of this intriguing occurrence remain a mystery. One suggestion is that the horse was fleeing a predator and it made its way to shallow water, but was swept away into to the middle of the lake where it eventually drowned. P. venticolus is the most primitive species of the Equidae family. This diminutive horse was only 20 inches (50 cm) tall at the shoulders and about two feet (60 cm) long as an adult. Interestingly, it had four padded hoofed toes on its front legs and 3 on its long hind legs. Its grinding teeth were well-suited to a diet of fruit and leaves, which were abundant in the subtropical climate that it inhabited. This specimen was discovered in the Fall of 2004 and is among the most scientifically significant specimens from the region. It garnered attention soon after it was unearthed: Dr. Lance Grande of the Field Museum examined the fossil and it later appeared in National Geographic Magazine. A museum-quality cast of the specimen currently on public display at the Fossil Butte National Monument in Kemmerer, Wyoming.