By Dale Gnidovec
The Columbus Dispatch
January 7, 2001
If I say rhinoceros, the word probably brings a certain picture
to mind. Five species of this animal exist, two in Africa and three
in Asia, all quite similar. Yet the rhinos of today are just a small
remnant of a once large and varied group.
Rhinos are ungulates, hoofed animals. Today there are two main
groups: artiodactyls (the even-toed ungulates, such as antelope,
sheep and bison) and perissodactyls (the odd-toed ungulates, including
horses, tapirs and rhinoceroses).
Rhinoceroses might well have originated here in America, and we
certainly have some of the best fossils. One of the earliest known
perissodactyls is Hyracotherium (sometimes called Eohippus) from
about 50 million years ago. About the size of a fox, it is often
called the first horse, although it could almost as easily be called
the first tapir or first rhino.
About 30 million years ago, there appeared a group of long-legged
hornless rhinos called hyracodonts, the running rhinoceroses. Hyracodon
was about 5 feet long and probably resembled a small pony.
At the other extreme is a group of giant rhinos that lived in Pakistan
and China at about the same time. Indricotherium (also called Baluchitherium)
was the largest land mammal known. Its skull was more than 4 feet
long, it stood 18 feet tall at the shoulder, and it might have weighed
About 11 million years ago, rhinos were among the most common animals
on the Great Plains. One kind, Teleoceras, was a short- legged,
wide-bodied form that resembled (and probably lived like) the modern
hippopotamus. Unlike modern rhinos, which tend to be solitary, Teleoceras
congregated in large groups, as shown by a herd of more than 100
that was buried by volcanic ash in central Nebraska.
During the Ice Age, at least two kinds of woolly rhinoceros appeared.
Russia was home to Elasmotherium, a large rhino with a single huge
horn on its forehead. The animal was of almost elephant proportions,
and the horn was more than 6 feet long.
The other woolly rhino was Coleodonta, which had two horns on its
snout, one in front of the other. Coleodonta ranged widely, from
Britain to Asia, but never reached North America. Not only have
corpses been found in frozen gravel in Siberia, but ancient humans
also drew detailed pictures of it on cave walls.
Rhinos aren't the only group to originate in North America, spread
to other lands in a variety of forms and then become extinct here.
I'll tell you about another such group next week.
Dale M. Gnidovec is curator of Ohio State University's Orton Geological