During the Oligocene, grasslands spread like prairie fire across the earth. To cope with this, many strange herbivores evolved. For instance, the first modern rhinoceroses, pigs, cattle, and deer appeared. Grasses had become a continual supply of food. In order to break down the large amounts of cellulose in grasses, herbivores developed extraordinary digestive systems. Chewed food traveled to the rumen (a four-part-stomach), where cellulose was constantly broken down a little, and then regurgitated to be chewed up more, broken down more, chewed, broken...until all of the cellulose was broken down. One kind of herbivore that developed during this succession of evolution were the brontotheres. Brontotheres had a Y-shaped bone on top of its snout. This particular appendage may have had uses in the jousting of rival males or for warding off enemies. Another herbivore was the gigantic Baluchiterum - the largest land mammal ever. Baluchiterum was 16 feet high and weighed 17 tons! The descendants of these creatures today are numerous and live all over the grass lands of the world. Will future generations consider the mammals of today are as weird as those of the Oligocene?

Cenozoic Era: Tertiary Period: Oligocene Epoch: Creature Feature