Toxodon. Illustration and photo-reconstruction of a Toxodon walking on the emerald grass of the South American savannah. Toxodon is an extinct mammal of the late Pliocene and Pleistocene epochs about 2.6 million to 16,500 years ago. It was indigenous to South America, and was probably the most common large-hoofed mammal in South America at the time of its existence. Toxodon was about 2.7 metres in body length, with an estimated weight up to 1.5 tonnes and about 1.5 metres high at the shoulder. It resembled a heavy rhinoceros, with a short and vaguely hippopotamus-like head. Toxodon would have had a very unusual gait, due to its peculiar proportions. It may have galloped to escape predators, but like a rhino, it probably relied more on its size as protection against predators.