We usually think of whales as serene, tender creatures, but a new study of an ancient species paints a different picture. However, about 35 million years ago, at the end of the Eocene, a giant whale swam across the ocean, feeding on large fish and, as evidenced by new data, in other, smaller whales.
Discovered in 2010, this 15-meter specimen of the ancient basilosaur whale (Basilosaurus isis) was associated with a number of remains of sharks, other fish and a smaller species of ancient whales, called the Dorudon atrox. In the course of the study, the results of which were published in the journal PLOS One, it turned out that these remains were not just next to each other, but in fact were prey to a giant whale. Basilosaurus was a formidable creature who lived 34-38 million years ago. Scientists have found samples of colossal size, reaching 15-18 meters in length. For comparison, modern killer whales have a length of 5-7 meters, and humpback whales – 13-16 meters.
According to the first author of the article and an employee of the Museum of Natural History in Berlin, Manja Voss (Manja Voss), the basilosaurus had a long face and was armed with pointed incisors and sharp cheek teeth. The animal itself, judging by the state of its teeth, was already quite old, and in its edge a shark tooth was found, which most likely belonged to the scavenger shark Carcharocles sokolowi, which ate the dead whale. The remains of this creature were found in a place that is known as the “valley of the whales”, south-west of Cairo in Egypt – it was here that a huge number of bones of ancient whales were found. On the place of the modern dry valley there used to be a shallow sea where all kinds of sea creatures lived.
The remains of B. isis were first found near other fossils of sharks, large bony fishes and young whales. Initially, it was difficult to say whether the basilosaurus was a scavenger or predator, like modern killer whales. A new study of small whale skeletons helped answer this question. In the “valley of the whales,” all skeletons of basilosaurs were adults, but about half of D. atrox were still minors, and the bones of their skulls had bite marks. According to the researchers, this may serve as the first direct evidence of the diet of this huge ancient whale.
“These observations led us to the idea that the shallow sea of the Late Eocene, which covers what is now considered the“ whale valley ”, was the breeding ground of D. atrox, and, therefore, the basilosaur’s hunting area,” scientists say in their article .
Thus, the researchers summarize, instead of being scavengers, basilosaurs were probably super predators (that is, occupied the top position in the food chain), like modern killer whales.