La Brea Tar Pit Riker Box Specimens

Above: The front of the Specimen Card for the Tar Pit Specimen. (Source:  Smilodon californicus and Canis dirus fight over a Mammuthus columbi carcass in the La Brea Tar Pits, Robert Bruce Horsfall, 1913)

The La Brea Tar Pits are among the most well-known petroleum seeps in the world. Over millennia, such seeps can become lake-like formations and trap unwary wildlife. Excavated animal remains at La Brea comprise nearly 700 different species, some dating back 40,000 years to the Late Pleistocene.