(order Perissodactyla, suborder Ceratomorpha)
A superfamily that comprises the rhinoceroses and their relatives, grouped into the families Hyracodontidae, Amynodontidae, and Rhinocerotidae. They are believed to have evolved from tapir-like forms and throughout most of the Tertiary they were abundant over most of the northern hemisphere. Many developed horns (the name is derived from the Greek rhino-, ‘nose’, and keras, ‘horn’) made from fused hair, and many attained large size, with short legs. Early forms possessed five digits, later forms four and then three, but no member of the superfamily has possessed fewer than three. The digits have nail-like hoofs. The brain is small, eyesight is poor, the most highly developed senses being those of scent and hearing. They are mainly nocturnal, solitary, and timid. Some graze in small herds.
Subjects: Zoology and Animal Sciences.