Stomach contents of the archaeocete Basilosaurus isis: Apex predator in oceans of the late Eocene

Apex predation in whales is revealed through the first direct evidence of diet in Basilosaurus isis, a late Eocene archaeocete from Wadi Al-Hitan, Egypt. Analysis of stomach contents shows it preyed on smaller whales (juvenile Dorudon atrox) and large fishes (Pycnodus mokattamensis), confirming a predator-prey relationship between the two most frequently found fossil whales in the site. This discovery extends understanding of their paleoecology and highlights Basilosaurus isis as an apex predator, akin to modern killer whales (Orcinus orca) and late Miocene Livyatan melvillei. The study underscores the need for greater attention on whales as apex predators throughout the Cenozoic era.

Voss, M., Antar, M. S. M., Zalmout, I. S., & Gingerich, P. D. (2019). Stomach contents of the archaeocete Basilosaurus isis: Apex predator in oceans of the late Eocene. Plos One, 14(1), e0209021. https://doi.org/10.1371/journal.pone.0209021