@2.5MYA - 10,000 YEARS AGO
Smilodon gracilis, Smilodon populator, Smilodon fatalis
|The animals most commonly thought of in terms of the evolution of the big cats (and my personal favorite) are members of the genus Smilodon. The genus is currently divided into three species : Smilodon gracilis, Smilodon populator, and Smilodon fatalis.|
Large numbers of these animals have been found in the famous tar pits at Rancho La Brea in California, making them among the most well known of the ancient predators. The animals full range actually extended throughout North and South America. The earliest species is Smilodon gracilis, known from about 2.5 MYA . It is also the smallest of the three.
|Smilodon populator was the largest. It was about the size of a modern lion, and was found mainly in eastern South America. This species appeared as early as 1 MYA. Smilodon fatalis is slightly smaller than S. populator. It ranged from North to South America.|
These cats existed until around 10,000 years ago, when the last became extinct. To compare, all three have coexisted with humans for thousands of years. It is estimated by some anthropologists that humans may have arrived in the Americas as early as 25,000 years ago, although most would estimate closer to 11,000 years.
RECONSTRUCTION OF THE GENUS
Much of the theories of the behavior of the Smilodon genus comes from the large sample at La Brea, which contains about 162,000 specimens from about 1,200 individuals. The evidence is as follows:
1.Smilodon has been found in large numbers associated with prey
2. Like most fossil cats, kittens show evidence of having heavy dependence on mothers due to their rate of development
3. Some wounded individuals show signs of healing
4. Other carnivores in the area included dire wolves, bears, cheetah like cats, and the large north American lion
|According to Alan Turner in his book "The Big Cats and Their Fossil Relatives, the first three points are evidence of Smilodon living in groups much like lions. I tend to agree with this theory. Most cats attack smaller prey, but lions are able to hunt buffalo and other large mammals with the aid of group cooperation. Social behavior would also be an advantage in helping more members survive, such as the case with cubs and wounded adults.||
The existence of lions and wolves in North America may also be pressure for social cooperation. Both predators are competing for the same food supply, and the group life of lions would be an advantage. Although this may not be evidence of Smilodon prides, it is not impossible to believe that social behavior would also become an adaptation of Smilodon in competition with the other social predators.
||As for coat coloring, that would depend on environment. The typical idea of a "saber-toothed tiger" with a striped coat would only be possible in wooded areas. Here, like modern tigers, the stripes would serve as efficient camouflage. In open grassland areas, it is more likely that Smilodon would have a more solid color like lions. The solid tawny brown of lions blends in with the grasslands, making them nearly invisible. In this case, stripes would be a disadvantage in revealing the animal to it's prey.|
The drawings on this page were made based off pictures and museum mounts I have seen of the skeletons of Smilodon. The coat pattern was based off a picture of a liger. I used a liger rather than a tiger because liger stripe patterns are more sparse and tend to be lighter than tigers. I believe that stripe patterns on Smilodon were perhaps not as bold as a tiger, since in most cases they appear to have lived in less densely forested areas than tigers. Here, a wider or more spot (or 'smudge') pattern may have been more adaptive, as it is in cheetahs and leopards. These two cats live in similar sparsely (if at all) wooded areas. Note in the above drawing of a male and female the fact the male has a slight mane. This is a completely parsimonious assumption, but perhaps male Smilodon had manes for social purposes. Lions as the only cats with manes are also the only ones that live in prides. Perhaps if Smilodon lived in prides, males would also have a mane to serve some social purpose within the group.
1. "The Big Cats and Their Fossil Relatives". Alan Turner. Columbia University Press. New York. 1997
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