Sharks ate the noses of sperm whales in Miocene Peru

Seven million years ago, sharks fed on the noses of sperm whales in search of fat reserves. This is indicated by a study carried out by Peruvian researchers, led by the paleontologist Aldo Benites Palomino, and which has just been published in the journal “Proceedings of the Royal B”.

The research sheds more light on the ecological relationships between these groups of animals, two of the most abundant in this area of ​​the planet during the Miocene.

In a conversation with El Comercio, Benites comments that it all started while he was analyzing the remains of new species of sperm whales at the Natural History Museum.

“We had a series of skullswhich were new species [de cachalotes]. The first step was to understand its anatomy, to describe the new species, such as ‘Kogia danomurai’ or ‘Scaphokogia totajpe’. However, between 2015 and 2016, I realized that all these little animals had some markings in common, with a very noticeable pattern. They were all in the area of ​​​​the face, very deep, which can only be left by sharks “explains the researcher.

scavenger attacks

For millions of years, Peru was covered by the sea and therefore the large number of marine fossils. “That explains the remains of a plesiosaur found in the Morro Solar or that the Andes mountain range is made of marine rocks”details Benites Palomino.

Thanks to current studies on how sharks attack whales and how they react to the remains of other animals floating in the sea, it was determined that they were their marks.

Most of the marks have been found in the surrounding bones, such as the maxillae and premaxillae, or in the region near the orbit of the eye. However, the general shape, size and arrangement of the bite marks is highly variable, suggesting that they were the product of a series of consecutive events and from different shark species.

The reason why these sperm whales -and, in particular, those areas of their bodies- were the target of attacks, would be the high concentration of fat. In modern sperm whales, the affected areas contain the spermaceti and the melon, organs rich in fats and oils.

Currently, modern sharks tend to go to areas of whale carcasses, with high concentrations of fat, such as visceral fat.

Although for the authors of the investigation, the attacks are related to scavenging events, they do not rule out that there have been episodes of direct predation against the pygmy sperm whale of the genus ‘Scaphokogia’, which is only 2.5 m long.

“In this study we present that sperm whales, in addition to being a very diverse community with different ecological niches, also fulfilled another role within the food chain: their carcasses were a repository of fat for sharks. All this at a very important time for the Peruvian sea, because it had the two largest predators living side by side: the ‘Lyvviatan melvillei’ [cachalote] and the ‘Otodus megalodon’ [tiburón]each with a large community behind […] Today we have sharks and sperm whales, but the ecological relationships that existed in those times were very different, and this study helps to understand it”, emphasizes the paleontologist Benites.