In September 2024, a river otter dragged a child underwater at a marina in Bremerton, Washington. While the child escaped with scratches and bites, this has not been the only attack recorded of the incredibly cute river otter.

“They’ll protect their mates, they’ll protect their young — they are like humans,” says Carin Wittnich, a senior scientist at the Oceanographic Environmental Research Society, a Canadian charity that focuses on aquatic species research.

Otter attacks can occur because of climate change, humans encroaching on formerly wild wetland areas, and in some cases, not enough public education on wildlife.

Otter Attacks are Rare

Wittnich and her colleagues published a pair of papers in the International Union for Conservation of Nature’s Otter Specialist Group Bulletin that surveyed scientific and news reports related to otter attacks.

The first was published more than a decade ago and covered all reports they could find to the end of 2011. They published a follow up in 2023 that covered the following 10 years.

In the first report, they found 39 reports, some dating all the way back to 1875. In the more recent decade, the team found 20 reports, three of which occurred in captive environments.

“You’re not talking a huge number here,” Wittnich says. “It’s not in-your-face horrendous.”

She acknowledges that many attacks likely go unreported, though. For example, Wittnich says that no reports were found of giant otters in South America attacking people in the wild. But since these animals are sometimes hunted for bush meat, it’s likely that bites occur but aren’t reported.

“It’s just a part of their daily risks,” Wittnich says.

The researchers also conducted their searches primarily in English, and may have missed reports in Spanish, Portuguese, or other languages in countries where otter species live.

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Otter Bites and Scratches

In all the cases Wittnich and her colleagues examined, only one report was fatal, involving a 96-year-old man in India who was bit by a smooth-coated otter — a species found in parts of South and Southeast Asia.

This case occurred when an otter cub was captured in a fishing net and pulled to shore while crying out in distress. A whole group of otters surrounded the man, biting and scratching him until they rescued the cub. The man later died of his injuries.

Other reported attacks ranged greatly; the study found. One case involved a person needing more than 200 stitches while other attacks were just small bites on fingers. Many of the bites were just puncture wounds from the teeth rather than a ripping or tearing gash.

Why Do Otters Attack?

Several factors likely influence otters to attack humans. Otters are often territorial. In some cases, as a result, Wittnich says, otters often just bite once and then back off — this is something of a warning to humans who have gotten too close.

Attacks can be more serious when otters feel cornered or trapped — in these cases they may do whatever they can to escape. And serious attacks can also occur when a mother is separated from its cubs by a human.

Rabies may also play a role in attacks. Between 24 percent and 66 percent of the cases, reported up to the end of 2011, confirmed rabies. This disease can cause increased aggression and decrease the fear of humans, which may lead to more attacks.

In the recent decade, rabies was only suspected in two of the cases but never confirmed. Regardless of the confirmation, bite victims are treated for rabies just to be safe.

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Habitat and the Climate

Rabies or no, the problem is related to humans and otters sharing the same spaces at the same time. Seasonally, more bites occur during the breeding, birthing and pup rearing months — a period when otters have cubs and are more protective as a result.

These summer months also coincide with the time when humans are out boating, swimming and walking river paths more often, as the weather is warmer. “The two [factors] come together in a perfect storm,” Wittnich says.

Another major factor is habitat loss and climate change. Dryer conditions can drive otters, and humans, into more concentrated bodies of water, Wittnich says, which in turn can lead to more bites. It can also affect their prey base, making otters more likely to travel into human areas they would otherwise prefer to avoid.

“All of that will contribute to bringing humans and otters together,” she says.

Reducing Otter Attacks

In general, Wittnich notes that a large portion of the attacks involve people under 20 years old. She suspects that this might be due to a lack of education among younger people.

In one case, a victim got bit after trying to warm an otter cub they thought appeared cold and weak. “People have to realize that wildlife has to be handled by professional,” Wittnich says.

Overall, many otter attacks on humans could have been avoided. “It’s not like they become mad-crazed otters that just see a human and jump on him,” Wittnich says.

She hopes that better regulation, and public education, could help to decrease the amount of otter attacks, which may only increase in some areas as the human population encroaches on the wetlands.

Article Sources

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

Joshua Rapp Learn is an award-winning D.C.-based science writer. An expat Albertan, he contributes to a number of science publications like National Geographic, The New York Times, The Guardian, New Scientist, Hakai, and others.