The small shark species that terrorizes all animals

They can grow up to 50 centimeters long. It's the fearsome cutter shark, known as the cookie cutter, which can rip chunks of meat off other specimens and whales much larger than itself.

There's a small species of shark that terrorizes animals of all sizes. It is the "cutter", or also called "cookie cutter", a fish that can rip pieces of meat even from other sharks or whales much larger than it. A member of the Dalatiidae family, it lives in tropical ocean waters. A study by the School of Marine Science and Policy at the University of Delaware found that they play a unique role in the ocean ecosystem.

The little cookie-cutter shark

The cookie-cutter shark gets its name from its habit of leaving perfectly round scars on its prey, similar to those on a cookie mold. It can grow up to 50 centimeters in length and, with its sharp teeth, can feed on even great white sharks 10 times its size. It is precisely their diet that gives them a special role in the ocean food chain.

"They feed on everything from the largest and most hardy predators, such as great white sharks and killer whales, to the smallest creatures," lead author of the new study Aaron Carlisle, an assistant professor in the School of Marine Science and Policy, wrote in a note. "There aren't many animals that do something like this," he added.

Research on cookie-cutter shark

The species lives at depths of 1,500 meters in tropical and subtropical waters, but can be spotted at night, when specimens approach the surface to hunt for larger prey. Researchers studied 14 cookie-cutter sharks captured around Hawaii from the Monterey Bay Aquarium to understand how their diet works. The team found out what they eat by looking at the chemical composition of their tissues and testing environmental Dna.

Environmental Dna "works with the idea that if an animal swims in the ocean, it will lose Dna in the water," Carlisle specified, "so if you take a sample of water and filter it, you can extract the Dna of everything that's been in that body of water and identify what species were there. This technique was tested by the team of researchers on the stomach contents of the cookie-cutter shark, and the result showed that the species feeds primarily on smaller animals at shallower depths, and that large animals in the upper ocean made up less than 10 percent of the sharks' diet.

Although incomplete, because the sample of sharks in the research was small and from a limited geographic area, the results still gave scientists important information about the ocean ecosystem that needs to be further investigated, however. Feeding on everything, what is certain is that they are probably among the most feared shark species of all.

Another research, however, found that shark teeth solve an ancient mystery related to climate. While among the most interesting marine species is the immortal jellyfish, capable of rejuvenation.

Stefania Bernardini