La Brea Tar Pits

The seep

Asphalt has seeped up here for tens of thousands of years

Natural asphalt has seeped upward from the ground here for tens of thousands of years. Sometimes it formed a deposit thick enough to trap animals, which the source calls a predator trap, because the predators that came to eat the trapped animals then became stuck as well. The oldest known material from the seeps has been dated to 38,000 years.

38,000years old, the oldest known material from the seeps

Chumash and Tongva

The Chumash and Tongva used the tar to seal their boats

The Chumash and Tongva people used tar from the pits to build plank boats, sealing planks of California redwood that had drifted into the Santa Barbara Channel. They used these boats to travel along the coast and to the Channel Islands. The tar was also used to form casts for broken bones.

1769

Spanish explorers named them the Tar Volcanoes in 1769

The Portolá expedition, a group of Spanish explorers led by Gaspar de Portolá, made the first written record of the tar pits in 1769. Father Juan Crespí wrote that scouts saw geysers of tar coming from the ground like springs, and the explorers named them Los Volcanes de Brea. In 1826 Harrison Rogers wrote that the people of the country used the asphalt to pitch the roofs of their houses.

The ranch

Bones lay in the tar for years before anyone saw they were fossils

The pits were once part of the Mexican land grant of Rancho La Brea. Tar-covered bones were found there for some years, but nobody recognized them as fossils, because the ranch had lost horses, cattle, dogs and even camels, whose bones resemble several of the fossil species. The land grant said that the tar pits were to be open to the public. There were originally more than 100 pits, and about a dozen can still be reached from ground level.