Fatal attack on a Rylands' bald-faced saki monkey (<Emphasis Type="Italic">Pithecia rylandsi</Emphasis>) by a black-and-white hawk-eagle (<Emphasis Type="Italic">Spizaetus melanoleucus</Emphasis>)

Predation risk has played an important role in primate behavioral evolution, yet natural primate–predator interactions are rarely observed. We describe the consumption and probable predation of an adult bald-faced saki monkey (Pithecia rylandsi) by a black-and-white hawk-eagle (Spizaetus melanoleucus) at the Los Amigos Biological Station in lowland Amazonian Peru. To our knowledge, this is the first published case of a black-and-white hawk-eagle consuming any primate species. We contend that while most reported observations of successful and attempted predation by raptors involves the largest and most notorious species (i.e. the harpy eagle), smaller and lesser known species like S. melanoleucus should be considered more seriously as a predator of neotropical primates. We discuss the predation event in the context of understanding what other neotropical primates might be vulnerable to S. melanoleucus predation given its body size and hunting tactic.