Sharks may not be responsible for rare human bites as we assume. In a study released today, scientists believe that at least some shark bites should be considered as a form of self-defense.
Marine biologists from France led the study, published in the field of conservation science. After analyzing shark bite data from around the world, they estimated that about 5% of human bites were completely defensive, rather than trying to capture the sharks for the next meal. The researchers say the findings should help inform shark bite prevention efforts.
The lead researcher of Eric Clua, a shark expert at PSL University, was inspired to investigate the topic through observations conducted in field studies in French Polynesia.
He often heard that fishermen systematically slaughtered sharks, which were unconsciously caught by fish pens. If these sharks initially fail to kill animals, they sometimes bite the fishermen. He also heard reports of sharks biting on underwater spearfish soldiers, where sharks appear to attack only because they want the fishermen to stay away from their prey.
“After careful examination, there is an opportunity to model this self-defense mechanism described in the study, which adheres to the responsibility of humans in this accident rather than sharks,” Krua told Gizmodo in an email.
The researchers first analyzed data on shark bites recorded in Polynesia, France – in particular, these events contained at least some information about the possible motivation behind the bites. Between 2009 and 2023, 74 such shark bites were recorded in the region. Researchers found that four of these bites may be motivated by self-defense.
Clua and his team then searched through data from the Global Shark Attack File, which has recorded nearly 7,000 shark bites. They examined bites classified as causing, involving people who are very close to sharks. Again, about 5% of the bites they studied (322 bites overall) seemed to meet self-defense standards.
These criteria include that sharks bite people immediately after human action, or that can be considered aggressive and that the bites are repeated but leave superficial, non-fatal wounds. Paradoxically, defensive shark bites may also be disproportionate compared to human effects, for example, where stranded sharks actively bite people in an attempt to return them to the water. But, according to Krua, this disproportion may be just a sign of sharks' desperate survival.
“The results of this study show that when the survival of a shark is threatened, the shark is as correct as any animal or human defense,” he said. “They also show that it is counterintuitive to advise against the help of a dangerous shark, as it does not necessarily give a positive view of this human action and may react positively.”
By discovering many motivations behind shark bites, the team hopes to stop them from happening in the first place. For example, people should not interact with or approach sharks even if they appear harmless or seem to be in danger. Overall, you should have at least two people when swimming where the shark lives, which reduces the risk of persistent predatory attacks. Krua added that unlike some land predators, keep it no Dissuading predatory sharks from attacking, so if the worst happens, you should always try to defend yourself.
Meanwhile, researchers point out that sharks are often afraid of humans. As a result, shark bites are very rare and are rarely fatal compared to other animal-human interactions.
For example, in 2024, only 88 shark bites were recorded worldwide, such as 7 related deaths. By contrast, hippos are estimated to have at least 500 fatal attacks per year, and when you consider the disease spread by certain animals, the death toll is increasingly varied (mosquito-borne malaria alone kills more than 500,000 people per year). So while it is important to practice good safety in water that may contain sharks, people (including journalists) should not over-inflate, and risk being bitten by them in the first place.
“In addition to reducing the number of bites in the field, we hope that one of the main effects of our study is to make humans more responsible by suggesting them to carefully study the conditions in which bites occur, rather than systematically blaming these animals,” Krua said.
The team plans to continue to study other types of shark bites, such as “exploration”-driven bites, where sharks may bite people to test whether they are suitable for prey.
