SMILODON FATALIS: CALIFORNIA’S STATE FOSSIL

Smilodon fatalis is well know to most people interested in late Pleistocene Ice-Age fossils, especially if they have visited the Rancho La Brea Tar Pits and Page Museum in Los Angeles. The word “Smilodon” means “scalpel” and is derived from: “two edged knife” combined with tooth.

Smilodon fatalis is the second most common (dire wolves are the first most common) large fossil found in the La Brea Tar (asphalt) pits in Los Angeles, California. Over 100,000 bones of S. fatalis have been recovered from these pits.

Figure 1. Plastic model of S. fatalis.

Figure 2.  Smilodon fatalis skeleton, Page Museum, Los Angeles, Los Angeles County, California. 

Smilodon fatalis was a true sabretooth cat, as opposed to the sabre-tooth marpusial carnivore, known as Thylacosmilus, which lived only in South America during the late Miocene and Pliocene. 

Sabertooth cats belong to the cat family Felidae. There are two subfamilies in this family: the extinct Machairodontinae (sabertoothed cats) and the extant Felinae (true cats).

In size and weight, S. fatalis was as large as a modern-day African lion, but unlike modern-day large predatory cats, S. fatalis was a stealth, ambush predator with strong front legs and relatively light hind legs. Thus, it was not a swift runner. Smilodon fatalis has only 26 teeth, fewer teeth than in other cats. Additionally, the sharp saber teeth (upper canines) of S. fatalis were most likely used stab into skin/flesh and/or bite open the soft underbelly of its prey, rather than biting into bones in order to subdue its prey (as in large cats living today). Also, the enlarged, but relatively narrow upper canines of S. fatalis have a distinct backward curve in order to minimize resistance and they have tiny serrations on the inside of the curve.

Figure 3. Smilodon fatalis skull.

 

Figure 4. Another Smilodon fatalis skull.

Figure 5. Smilodon fatalis canine tooth; 9 inches (23 cm) long from “tip to bottom of tooth.” Widest part of tooth is 1.5 inches (4 cm).

Figure 6. Closeup of previous image of S. fatalis canine tooth. Notice the presence of tiny serrations on the inside edge of this canine. 

Figure 7. Smilodon fatalis jaw muscles (exhibit at Page Museum).

Figure 8. Smilodon fatalis skulls showing progressive replacement of canine teeth (exhibit at Page Museum).

Smilodon is known only from Cenozoic deposits in North and South America. There are three known species. They are from oldest to youngest:  S. gracilis [2.5 mya to 500,000 years ago] and known only with certainty from North America; S. fatalis [1.6 mya to 10,000 years ago] and known only with certainty from North America (California, Texas, Mexico, Nebraska, and Florida]; and S. populator [1 mya to 10,000 years ago] and known only from South America (Wikipedia, 2023). The occurrence of the land bridge (GABI = Great American Land Bridge, which enabled exchange of species between North and South America during the late Pliocene [see one of my earlier posts on GABI], was responsible for the dispersal of Smilodon from North America to South America. Smilodon populator  Berta (1985) did detailed research on the South American species Smilodon populator.

Figure 9. Smilodon gracilis. This skull, which is/was on display at the San Diego Museum of Natural History, is most likely from Southern California (Anza Borrego Desert region). According to Shaw and Cox (1986), fossils of this sabertooth cat have also been found in Florida

and Pennsylvania. 

References Used:

Berta, A. 1985. The status of Smilodon in North and South America. Contributions in Science, no. 370, 14 pp. [free pdf]

Lindsey, E.L. (ed.). 2018. Rancho La Brea: Treasures of the tar pits. A Natural History Museum of Los Angeles County publication. Third edition. 72 pp.

Savage, R.J.G. and M.R. Long. 1986. Mammal evolution, an illustrated guide. British Museum (Natural History). 258 pp.

Shaw, C.A. 2001. The sabertoothed cats. In, Rancho La Brea: Death Trap and Treasure Trove, pp. 26–27. Terra. Natural History Museum Special Edition, v. 38, no. 2.

Shaw, C.A. and S. Cox. 2006. The large carnivorans: Wolves, Bears, and Big Cats. In Fossil Treasures of the Anza-Borrego Desert. The last seven million years. Sunbelt Publications, San Diego, California. 394 pp.

Stock, C, (revised by J.H. Harris). 1992. Rancho La Brea, a record of Pleistocene life in California. Seventh edition. Natural History Museum of Los Angeles County, Science Series 37, 113 pp.

en. Wikipedia. 2023. Smilodon.