It was the prey of predators like the big cat Smilodon and the Terror-Bird Phorusrhacos.
They could reach 3 metres long and 1.5 metres tall at the shoulder, and females lived in herds, a good way to protect their young.
They were herbivores, eating the grasses which had recently spread around the world. Their most unusual feature was the trunk, which is thought to exist due to their nostril structure.