Pachyrukhos is an extinct genus of mammal from the Oligocene and Miocene of South America. It was about 30 cm (1 ft) long and closely resembled a rabbit, possessing a short tail and long hind feet. Pachyrukhos was probably also able to hop, and it had a rabbit-like skull with teeth adapted for eating nuts and tough plants. The complexity of its hearing apparatus in the skull suggests that its hearing would have been very good, and that it probably had large ears. It also had large eyes, suggesting that it may have been nocturnal. These similarities are the result of convergent evolution, since, while quite unrelated to modern rabbits, Pachyrukhos filled the same ecological niche.