Dominant Fossils Found in the Haystack Assemblage:

Daphoenus socialis (bear-dog) Hypolagus sp. (rabbit) Moropus oregonensis (chalicothere) Daeodon humerosum (entelodont/ giant pig-like animal) Parahippus pawniensis (horse) Ursavus sp. (bear) Miotapirus harrisonensis (tapir) Paratylopus sp. (camel relative) Poplus Ginkgo

Charismatic Fossils

Daphoenus socialis, more commonly referred to as “bear-dog,” shared relatively the same proportions as an early dog while having a heavy build similar to a bear. This extinct mammal would have preyed on many smaller animals such as Hypolagus but would have also gone for larger game like horses or camels if it hunted in packs.

Hypolagus sp. was much like Archaeolagus mentioned above. This species was similar to the modern rabbit that grazed on low vegetation. Like rabbits today, its teeth grew throughout life.

Moropus oregonensis was a large perissodactyl (odd toed) that moved about on clawed feet instead of hooves. Much like a giant ground sloth, it would have used its claws to bring food down from low hanging branches or aid in its defense from predators. Moropus means “slow foot,” as the name implies its clawed feet and pigeon-toed gait made this calicothere a clumsy mover.