Odd-Toed Ungulates: Perissodactyla

Rhinos are solitary creatures seldom seen in pairs other than the mother-offspring combination. Even mated pairs don't remain together. Rhinos are territorial and have obvious displays to prove their authority, including rolling eyes, lowered head, and strutting. Males engage in brutal fights, and African rhinos inflict injury by jabbing each other with upward blows of their horns. Rhinos enjoy wallowing in mud holes because it helps keep their body temperature down and repels insects.

Female rhinos are ready to breed between the ages of three and five years. Gestation is fifteen to sixteen months in all species but the Sumatran rhino has a gestation period of seven to eight months. Mating often takes hours to complete and usually results in the birth of one calf. Rhinos weigh 55 to 145 pounds (25 to 65 kilograms) at birth and drink up to 5.5 gallons (25 liters) of their mothers' milk each day to gain 5.5 pounds (2.5 kilograms) daily. Zebras drink their mothers' milk for up to four years, though the white rhino begins eating solid food by one week of age. Males begin breeding at age ten and rhinos can live up to fifty years. What was true in the past remains true today: humans are the main predator, hunter, of rhinos.

Tapirs are also solitary mammals. They spend part of the day wallowing in mud or standing water, or simply rest in the shade. Territorial by nature, tapirs mark their territory with their urine. Most activity takes place at night. Tapirs swim with ease and water is at the center of their existence. Water provides not only food, but also safety from intruders. Able to hold their breath for minutes at a time, tapirs will seek safety from predators by immersing themselves in water. They have an acute sense of smell and hearing, but like other perissodactyls, cannot hear well. Though usually silent, they do communicate through grunts and whimpers at closer range, through whistles over greater distances.

Tapirs are sexually mature at two to four years of age. They breed year round, and females are receptive every two months. Courtship is a noisy affair. One baby is born after a gestation (pregnancy) period of 383 to 395 days. Young tapirs stay with their mothers until six to eight months of age. Tapirs have been known to live for thirty years. The primary predator of tapirs is the jaguar.

Unlike their relatives, horses are highly social. Zebras live in families of ten to fifteen individuals. These families include a territorial male, several females, and their offspring. Home ranges overlap with ranges of other families, and measure anywhere from 31 to 232 square miles (80 to 600 square kilometers). Zebras communicate via vocalization and adult males are especially noisy at night. Within groups, other males are tolerated, but only the territorial male may mate with the numerous females of the family. The black and white stripes of the zebra trigger visual neurons that attract males and females to each other. Zebras are believed to see in color, and they have binocular vision in front.

Horses are sexually mature around the age of two years, but males do not breed until around the age of five. After a gestation period of about one year, a single foal is born. The baby is able to walk on its own within an hour of birth and doesn't mind being left alone while the mother replenishes her water supply. Offspring are weaned (removed from mother's milk) at six to thirteen months. Some horses live to see forty years. Lionesses and hyenas are the main predators of horses.