<P> Among the prehistoric species associated with the La Brea Tar Pits are Pleistocene mammoths, dire wolves, short - faced bears, ground sloths, and the state fossil of California, the saber - toothed cat (Smilodon fatalis). </P> <P> Only one human has been found, a partial skeleton of the La Brea Woman dated to approximately 10,000 calendar years (c. 9,000 radiocarbon years) BP, who was 17 to 25 years old at death and found associated with remains of a domestic dog, and so was interpreted to have been ceremonially interred . John C. Merriam of the University of California led much of the early work in identifying species in the early 20th century . </P> <P> The park is known for producing myriad mammal fossils dating from the last glacial period . While mammal fossils generate significant interest, other fossils, including fossilized insects and plants, and even pollen grains, are also valued . These fossils help define a picture of what is thought to have been a cooler, moister climate in the Los Angeles basin during the glacial age . Among these fossils are microfossils, which are retrieved from a matrix of asphalt and sandy clay by washing with a solvent to remove the petroleum, then picking through the remains under a high - powered lens . </P> <P> Tar pits around the world are unusual in accumulating more predators than prey . The reason for this is unknown, but one theory is that a large prey animal would die or become stuck in a tar pit, attracting predators across long distances . This predator trap would catch predators along with their prey . Another theory is that dire wolves and their prey may have been trapped during a hunt . Since modern wolves hunt in packs, each prey animal could take several wolves with it . The same may also hold true of the saber - toothed cat (Smilodon fatalis) known from the area . </P>

When was the la brea tar pits found