The asphalt deposits of Rancho La Brea are well known for preserving a prolific and diverse Late Pleistocene fauna. However, little taphonomic research has been done on these collections. To better understand the formation of this impressive assemblage, a taphonomic study of the bones of the large mammals from one asphalt deposit, Pit 91, was carried out, and results are presented here. The predominance of carnivore specimens in the Rancho La Brea deposits has long been explained by a scenario in which a prey animal was trapped in asphalt and attracted large numbers of carnivores who became trapped in turn. Hypotheses generated from this scenario were tested by collecting taphonomic data on over 18,000 specimens. Weathering data indicate that elements were deposited fairly rapidly. However, patterns of skeletal part representation for the seven most common species demonstrate that complete skeletons are not present. Water transport is ruled out as the primary process responsible for removing skeletal elements based on abrasion data. Instead, the feeding activity of carnivores (ravaging) appears to have been an important factor in the formation of the assemblage.