By Yvaine Ye
Millions of years ago a mega whale species roamed the oceans. Now an analysis of their stomach contents reveals they may have been top of the food chain, and even eaten other whales.
Basilosaurus isis could grow to 18-metres in length, three times that of orcas. They lived 38 to 34 million years ago in the Atlantic Ocean near modern North Africa.
Nine years ago, a skeleton of a B. isis was found in northern Egypt, and it wasn’t alone. Fragmented bones from several fish were also unearthed from the same site. Scientists identified at least two smaller ancient whales, a bony fish and a shark.
Manja Voss at the Museum of Natural History in Berlin and her colleagues analysed the location of the other bones relative to B. isis. They found all of them were clustered in or near the B. isis’ rib cage, where the its stomach would have been. Additionally, deep bite marks were found on the skulls of the smaller whales that match the shape of B. isis’ teeth.
These suggests that B. isis had the ability to actively attack and prey on smaller whales and sharks that were also teethed predators that consume other animals. B. isis was at the top of the food web, making it the apex predator in its ecosystem, says Voss.
“This is the first stomach content found in B. isis, and also first direct evidence for diet in that species,” she says. “The study extends our knowledge of ancient whales and completes the bigger paleo-ecological picture.”
Journal reference: PLoS ONE, DOI: https://doi.org/10.1371/journal.pone.0209021
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