Lonely dolphin looking for mate blamed for attacks
A dolphin, believed to be lonely and possibly experiencing sexual frustration, has been linked to a surge in attacks on swimmers in a seaside town in Japan.
This bottlenose dolphin is suspected of being responsible for 18 attacks near the town of Mihama this year alone, one of which left a primary school-aged child needing over 20 stitches on their finger.
Last year, at least six people were injured in similar incidents, with one swimmer suffering broken ribs. Another person was injured in a 2022 attack.
Authorities have since issued warnings, highlighting that dolphins, despite their friendly reputation, can “bite with sharp teeth and cause bleeding” and even “drag people into the sea, which could be life-threatening.”
Though dolphins are often seen as benign creatures, attacks can be deadly. In 1994, a dolphin in Brazil fatally attacked a swimmer and injured another after they attempted to ride it. The dolphin, known as Tião, had reportedly harmed at least 22 people prior to the fatal encounter.
Tadamichi Morisaka, a cetology professor at Japan’s Mie University, noted that a dolphin spotted biting a man’s fingers at a Tsuruga beach had a dorsal fin matching that of a 2.5-meter-long dolphin observed off Fukui province’s coast the previous year. The dorsal fin, much like a fingerprint, is unique to each dolphin, with distinctive notches, ridges, and coloration.
“It is reasonable to assume that it is the same individual, as the wounds on the tail fin are similar to those of the dolphins seen off the coast last year, and it is rare for dolphins, which normally move in groups, to be alone for such a long time,” Prof Morisaka told NHK.
He added that male bottlenose dolphins communicate by “play-biting each other”. “They are not trying to injure people, but are using the dolphins’ way of communication with people,” he said.
Others have suggested various theories on why the same creature may be behind these attacks – including a desire for sex.
“Bottlenose dolphins are highly social animals and this sociality can be expressed in very physical ways,” said Dr Simon Allen, a biologist and principal investigator with the Shark Bay Dolphin Research project.
“Just as in humans and other social animals, hormonal fluctuations, sexual frustration or the desire to dominate might drive the dolphin to injure the people it interacts with. Since they are such powerful animals, this can lead to serious injury in humans.”
Dr. Allen added that the dolphin may have been “ostracised from its community and be seeking alternative companionship”.
Dr. Matthias Hoffmann-Kuhnt, a marine mammal expert at the National University of Singapore, said the dolphin could also be acting in its own defense.
“Most of the time, in my experience, this is more a defensive behavior when humans get too close to these dolphins and do not know how to conduct themselves,” he said, referring to reports of people trying to ride the animals or sticking their fingers into the dolphins’ blowholes.
“Thus it is no wonder that the animals then turn aggressive or at least protective against humans in the water,” he said.
It could also be that the dolphin previously had a bad encounter with a human being and now projects that relationship onto other humans it encounters, Dr Hoffmann-Kuhnt said.
“They have good memory, similar to elephants who will remember who mistreated them before,” he said.
