Indricothere

The huge indricotheres of the Oligocene were the largest land mammals ever to have lived. They were just larger than the Colombian mammoth, and the largest of the deinotheres.

Although they are members of the rhino family, they became adapted to browsing the tops of trees like modern giraffes. Their whole body was stretched upwards to do this, with very long legs and a long neck.

The fossils show that males were slightly bigger than females, with slightly more domed and reinforced skulls, suggesting that the males fought rather like modern giraffes.

Traits & Evidence
Indricotheres had flat, grinding back teeth, and tusk-like front teeth which would have helped it yank off leaves and shoots.

The indricotheres were built like modern giraffes, with very large heads on long necks. Modern giraffes have domed skulls and fight by entwining their necks and swinging their heads against each other. It is possible that the indricotheres fought in a similar way as males have larger and more highly domed skulls than the females.

The length of time a baby stays with its mother is highly variable in animals, but can be estimated. Once she had given birth, the mother would probably feed the youngster for at least a year. Baby elephants start to eat vegetation at around 6 months old, but still feed on milk until they are about 3 years old. The mother would start to become sexually receptive again once her body had started to recover from the pregnancy and lactation, so probably after about a year and a half, when the baby was feeding much more on vegetation. Then she would have a 2-year pregnancy and it would make sense for her to tolerate the calf being with her, although not feeding on milk much. So the calf would be around 3 and a half years old by the time her next calf was born.

The length of time a baby stays with its mother is highly variable in animals, but can be estimated. Once she had given birth, the mother would probably feed the youngster for at least a year. Baby elephants start to eat vegetation at around 6 months old, but still feed on milk until they are about 3 years old. The mother would start to become sexually receptive again once her body had started to recover from the pregnancy and lactation, so probably after about a year and a half, when the baby was feeding much more on vegetation. Then she would have a 2-year pregnancy and it would make sense for her to tolerate the calf being with her, although not feeding on milk much. So the calf would be around 3 and a half years old by the time her next calf was born.

Rhinos are usually pretty solitary animals, and the similar brain size of indricotheres suggests that they lacked the complex social herd structure of elephants, where the brain is used to remember all the individuals in the herd and their relationships. Instead rhinos tolerate their calves being with them until they give birth again, at which point the previous calf is nothing but a risk to the new-born and so is driven away.

Indricotheres' skulls show that they had very large nasal passages, meaning that they had a very good sense of smell. This is like modern rhinos, where the nasal passages are actually larger than the brain. This suggests that they used scent to communicate, just as modern rhinos do. An important part of this is scentmarking by spraying urine, and being able to detect the scent of an individual from dung.

Appearance
The biggest, male indricotheres stood around 4.5m tall and weighed around 15 tonnes. Early reconstructions made them extremely bulky and heavier, however current opinion is that the animals were slimmer than their modern relatives, the rhinos. The females of this largest species were probably smaller, weighing around 12 tonnes. Very large animals have trouble with overheating as they have a huge bulk of heat-producing muscle but only a limited surface area over which to lose it. That is why large animals tend to have little or no hair, and being the largest land mammal ever, the indricotheres are likely to have had skin very like their modern cousins, the rhinos.

In Walking with Beasts
Indricothere appear in both the episode Land of Giants, and the opening sequence for every episode.