Humans are greater threat to sharks, not the other way around

June 27, 2016 by Joann C. Adkins, Florida International University
Credit: Florida International University

Fans of Shark Week are sinking their teeth into a whole new slate of programming focused on one of the world's most fascinating predators. While Shark Week often delves into the sensational aspects of sharks, Florida International University (FIU) biologists are quick to remind people that sharks aren't exactly the voracious predators we often fear. In fact, shark attacks on humans are rare.

The rarity of these events makes it difficult to pinpoint the exact reasons why sharks attack humans. But FIU biologist Yannis Papastamatiou says a variety of reasons could be to blame, depending on the nature of the attack.

"It could be defense if the shark feels threatened. It could be an investigation of an unknown object," he said. "Very rarely, it could be for feeding."

In some cases, according to FIU marine scientist Mike Heithaus, a shark may actually mistake a human for a more traditional type of prey, such as a seal or sea lion. But Heithaus and Papastamatiou point out that no one, other than the shark, really knows what a shark is thinking when it attacks a human.

"We know that most sharks that bite a human rarely consume their victim, so they don't seem to like us as prey," said Papastamatiou, who uses acoustic and satellite technologies to study black tip reef sharks, leopard sharks, great whites, tiger sharks, stingrays and more.

Contrary to popular belief, sharks are much more docile than their pop culture persona. Studying the ecological role of large sharks both in Australian and Florida waters, Heithaus currently conducts research using cutting-edge technology, including cameras worn by animals, to unravel the lives of hard-to-study marine creatures from whales and dolphins to sharks, seals and turtles.

"Though they are fascinating creatures, sharks actually lead pretty boring lives," Heithaus said. "Footage captured by FIU researchers from cameras attached to the backs of sharks proves they mostly swim all day doing nothing in particular. Some, like nurse sharks, spend a lot of their time lying around."

The reality is sharks are much more threatened by human activity than the other way around. FIU research suggests as many as 100 million sharks are taken from the oceans every year, a pace sharks cannot keep up with. This is leading to population declines that are cause for concern among scientists worldwide. To advance conservation efforts, Heithaus, FIU marine scientist Demian Chapman and a team of international researchers are conducting a global survey of shark and ray populations called Global FinPrint.

"Sharks are impressive animals with complex behaviors," Heithaus said. "Recently, we have begun to find that sharks have personalities. Some individuals are bold. Others are less so. They are able to modify their behavior in response to changes in their environment, and some species have been taught to navigate mazes. We are still learning much more about the behavior and cognitive abilities of ."

Heithaus will be featured at 10 p.m., June 29, in Discovery Channel's Sharks vs. Dolphins: Face Off.

Explore further: Shark census reaches first 100 reefs: Early findings of global survey show existing data may be inaccurate

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