A lone dolphin believed to be sexually frustrated as it cannot find a mate is behind attacks on swimmers in a Japanese seaside town.

The bottlenose dolphin is believed to be responsible for 18 attacks near the town of Mihama. In fact, according to the BBC, so far this year, he injured a small child’s finger, which required at least 20 stitches.

Last year, 6 people were injured in similar attacks while another swimmer ended up with broken ribs. Also another person was injured in 2022.

The incidents led authorities to issue an advisory to swimmers warning that the otherwise cute mammals can “bite you with their sharp teeth and cause you to bleed”, but can also “drag you into the sea, which it could be life-threatening.”

Are dolphins really dangerous?

Despite their reputation as friendly animals, dolphin attacks can be deadly.

In 1994, a dolphin in Brazil attacked two swimmers who tried to ride it, killing one and injuring the other. The dolphin, nicknamed Tião, is believed to have injured at least 22 people.

Tadamichi Morisaka, a cetacean professor at Japan’s Mie University, said the dorsal fin of a dolphin spotted biting a man’s fingers on a beach in Tsuruga – a port city next to Mihama – matched that of a 2.5m dolphin observed off Fukui. province last year.

The dorsal fin is like a dolphin’s fingerprint, as each has distinctive notches and ridges.

How did they find the culprit?

“It is reasonable to assume that this is the same dolphin, as the injuries on the tail fin are similar to those of the dolphins seen off the coast last year. It is rare for dolphins, which usually move in groups, to be alone for such a long time,” Professor Morisaka told NHK.

He added that male bottlenose dolphins communicate by “play-biting each other”. “They’re not trying to hurt people, but they’re using the way dolphins communicate with people,” he said.
Others have proposed various theories as to why the same creature might be behind these attacks – including a desire for sex.

“Minor dolphins are highly social animals and that sociality can be expressed in very physical ways,” said Dr Simon Allen, biologist and principal investigator on the Shark Bay Dolphin research project.

“Just as in humans and other social animals, hormonal fluctuations, sexual frustration or a desire for dominance may lead the dolphin to injure the people with whom it interacts. Since they are such powerful animals, this can lead to serious injury to humans.”

Dr Allen added that the dolphin may have been “exiled from its own community and is looking for alternative companionship”.

Dr Matthias Hoffmann-Kuhnt, a marine mammal expert at the National University of Singapore, said the dolphin could be defending itself. “Most of the time, in my experience, this is more of a defensive behavior when people approach these dolphins and they don’t know how to behave,” he said, referring to reports of people trying to ride the animals or stick their fingers in the holes. of dolphins.
“So it’s not surprising that the animals then become aggressive or at least protective of humans in the water,” he said, concluding “They have a good memory, similar to the elephant. They remember who abused them before.”