Megacerops, a large perissodactyl mammal from the late Eocene, was one of the largest known brontotheres. Reaching up to 5 meters long and weighing over 2.5 tons, it resembled a robust rhinoceros but was more closely related to horses. Its most striking feature was the paired, bony, Y-shaped protrusions on its snout, which were likely covered in keratin and used in male-male contests, similar to the antler fights of modern deer.

This giant herbivore inhabited the open plains and sparse forests of North America, where it fed on leaves and tall branches. Like other brontotheres, it had strong limbs, adapted more for supporting its weight than for running fast. Megacerops likely lived in groups, and its horns played an essential role in social interactions and defense against carnivorous predators, such as the large, nimravid felines of the time.