State authorities are searching for a group of violent river otters (Lutra canadensis) that have been mysteriously attacking adults, children and dogs in Anchorage, Alaska.
Three otter attacks —including one which injured a child — were reported across the city in September, leading officials from the Alaska Department of Fish and Game (ADFG) to ask residents to "be alert around local lakes and rivers."
Nine-year-old Ayden Fernandez was filming four otters in a duck pond with his brother when one of the animals split from its group and attacked him. He tripped and fell as he was chased, and the otter pounced on him.
"He has two fang marks on his back thigh, and one on the front thigh on each leg," his mother, Tiffany Hernandez, told Anchorage Daily News. "[He has] one puncture wound on his foot. He ended up falling as he was running away and [the otter] got him on his back."
Ayden was taken to the emergency room, where he received a rabies vaccination and booster. Two more attacks followed later in the month, both occurring on the same day, according to the ADFG. In the first an otter bit a woman who was rescuing her dog from the group. In the second, reported from the same lake, otters attacked a second dog.
This isn't the first time that otters have attacked dogs in the city. In two separate incidents in 2019, two dogs, one labradoodle and a husky-mix, were attacked and pulled underwater by otters while swimming in lakes in Anchorage, Huffpost reported. The owner of the husky-mix had to jump in after his animal to fight off the otters. Both dogs survived, but had received bites and slashes that required multiple stitches.
Although no one knows how many otters are behind these incidents, David Battle, a wildlife biologist at the ADFG, suspects that it may be just one group.
"There always seem to have been four or five otters involved in all the incidents," Battle told Live Science. "Considering the rarity of this behavior in otters, and the fact that our first reported attack was in 2019 and it’s happened several times since then, this is very likely one group that has stayed together for a while or that come together frequently over a period of time."
Otter groups tend to consist of either a mother with pups or several bachelor males. Battle said that as multiple otters were reported engaging in attacks, it’s likely that the group is a collection of adult otters, as opposed to a mother otter defending her young. Given the involvement of dogs in nearly all of the incidents, the most probable explanation for the otters’ aggressive behavior is a defensive reaction to dogs.
"Most otters never display this strong a reaction to dogs or people. By and large, they are curious animals, but not typically aggressive toward people or dogs," Battle said. "It’s possible there was some sort of incident involving a dog that led them down this path, after which the otters learned to take aggressive action against dogs, but it’s impossible to say."
A 2011 analysis by the Oceanographic Environmental Research Societyfound that since 1875, people have reported 39 wild otter attacks across the United States.Of these, 15 took place in Florida alone, and 24 of the assailant otters had rabies. Otters usually only inflict minor injuries on humans and none of the attacks were fatal, but in one of the most extreme cases, a victim of a particularly brutal otter attack had to receive nearly 200 stitches. In a notable case in 2018, a 77-year-old Florida woman was viciously attacked by an otter while paddleboarding in Florida, Live Science previously reported.
The ADFG are searching for the otter group responsible for this most recent spate of attacks, but Battle believes that given the animals’ lack of any fixed territory, as well as their ability to move extensively through interconnected waterways, tracking them down could be tough. Once the otters are found, the ADFG says it will remove individuals from the group, testing any otters killed in the process for rabies.
"Identifying the individuals involved will most likely be a matter of responding to sightings and evaluating behavior when we’re able to catch up to them — what their reaction is to the presence of people, dogs, etc," he said.
Originally published on Live Science
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Ben Turner is a U.K. based staff writer at Live Science. He covers physics and astronomy, among other topics like tech and climate change. He graduated from University College London with a degree in particle physics before training as a journalist. When he's not writing, Ben enjoys reading literature, playing the guitar and embarrassing himself with chess.