Trophic interactions between sharks and other marine vertebrates are represented by both indirect and direct evidence from the fossil record. Indirect evidence includes such traces as shark tooth marks and gouges on the bones of prey, such as fish, reptiles, whales, dolphins, and seals. Direct evidence is represented by the presence of shark teeth in definite association with prey species. In this paper, we report direct evidence for trophic interactions between a white shark (Carcharodon sp.) and a mysticete whale from the lower Pliocene (∼4-5 Ma) Pisco Formation of Peru: a partial mandible of an unidentified mysticete whale with a partial tooth of a white shark embedded within the cortical bone. Modern white sharks are known predators of many marine mammal species, and both active hunting and scavenging have been well documented. In this instance, we interpret this specimen to represent a scavenging event. This fossil is unusual because it represents a seldom-reported event that preserves direct evidence of trophic interactions. Copyright © 2009.