Hiking Through the Ice Age: Smilodon vs. Uintatherium

By Jack Shimon, Colorado Springs Mineralogical Society Pebble Pups
With web support by Julie Shimon

If you saw these animals in real life out on a hike which one would you be more frightened of?

Figure 1. Uintahtherium skull



Figure 2. Smilodon skull

The skull in figure 1 is from an animal about the size of a rhinoceros. The skull in figure 2 is from an animal about the size of a tiger. They both have long canines. So when I saw these skulls at the Morrison Natural History Museum, Colorado on a field trip with my family I told the lady that asked me about them that they were probably both carnivorous saber tooth tigers.

How wrong I was. She told me all about them. On the Uintatherium (figure 1) the canines were the obvious thing I looked at. I think they like to trick people because the skull of Smilodon fatalis is hanging just above it on the wall. But when you take a closer look they are actually very different.



Figure 3. Another view of a Uintahtherium skull



Figure 4. Front view of a Smilodon fatalis skull

If you think about the size, an animal with a skull as big as Uintatherium would make a gigantic cat. Much bigger than any cat I can think of, and even huge in comparison to the Smilodon. The canines are long, but not nearly as long or sharp as that of Smilodon and unlike Smilodon, Uintatherium has no front teeth like most predators. Uintatherium also has long plates of flat teeth used for grinding. I finally had to accept the fact that this animal was an herbivore!!!

It’s funny the museum had these on display together because not only are they entirely different animals but they also lived millions of years apart. Uintatherium (Beast of the Uinta) lived in the Eocene Epoch and went extinct 37 million years ago, probably due to climate change. They have been found only in Wyoming and Utah near the Uinta Mountains, which they are named for (“Wikipedia”, 2011). I think they didn’t have to roam far to feed because they ate all sorts of land and aquatic plants. They are similar in size and shape to a rhinoceros but not related at all. Modern rhinos weigh from 1,900-7,700 lbs which is a LOT more than Smilodon, and Uintatherium was probably similar in weight to the rhino (“Wikipedia”, 2012).

So why do they have those long canines? Maybe they were used to defend themselves but it was also suggested they used them to scoop plants from the marshes to feed on (“Wikipedia”, 2011). We might never know.

Figure 5. Artist's rendition of the Uintahtherium

There are three main species of Smilodon (also known as saber-tooth cats) and S. fatalis was middle in size between S. gracilis (smallest) and S. populator (largest). Smilodon went extinct in the late Pleistocene about 11,700 years ago, also probably due to climate changes. They were highly specialized top predators feeding on large game like bison, tapirs, deer, horses, sloths and possibly juvenile mastodons and mammoths. They also may have attacked prehistoric humans. S. fatalis was about the size of a Siberian tiger, an weighed up to 500lb; but built more like a modern day bear--robust for power--not speed. Smilodon canines have been measured up to 28 cm long and were used to slice through the throat after the powerful legs pulled the prey down. S. fatalis had a large range, from North America into West South America (“Wikipedia”, 2012). I wonder if Smilodon had met Uintatherium who would have won? I don’t think it would be very smart for Smilodon to try to eat Uintatherium.

Figure  6. Artist's rendition of S. fatalis

I have definitely decided that if I were to meet these creatures on a hike that I’d rather run into Uintatherium. He definitely wouldn’t try to eat me although that large skull still looks very scary.

Note: author's bio follows references. Jack Shimon is a frequent contributor of papers, poems, articles, and monographs on geoscience subjects.

References:
Interview by JS Shimon [Audio Tape Recording]. Museum tour. , Retrieved from http://www.mnhm.org/

Wikipedia. (2011, December 26). Retrieved from http://en.wikipedia.org/wiki/Uintatherium

Wikipedia. (2012, February 22). Retrieved from http://en.wikipedia.org/wiki/Rhinoceros

Wikipedia. (2012, February 15.). Retrieved from http://en.wikipedia.org/wiki/Smilodon

Author's bio:

Jack Shimon is seven years old and a first grade student in Colorado Springs, CO. Under the guidance of his grandfather he got interested in geology at a young age and has been on numerous rock and fossil collecting trips in Colorado and Texas. He's been a member of Pebble Pups since 2009 and has earned seven merit badges through that program. His other interests include cub scouts, drumming, mountain biking and rock climbing.