Editor
A lonely and doubtlessly sexually annoyed dolphin has been blamed for a spike in assaults on swimmers in a Japanese seaside city.
The bottlenose dolphin is believed to be behind 18 assaults close to the city of Mihama up to now this yr, with one major school-aged kid’s finger needing at the very least 20 stitches.
At least six folks had been injured in assaults final yr, leaving one swimmer with damaged ribs. Another particular person was injured in a 2022 assault.
It has led officers to warn that not solely can the mammals “chew you with their sharp enamel and trigger you to bleed”, however they’ll additionally “drag you into the ocean, which may very well be life-threatening”.
Despite their repute as pleasant animals, dolphin assaults may be deadly. In 1994, a dolphin in Brazil attacked two male swimmers who tried to experience it, killing one and injuring the opposite. The dolphin, nicknamed Tião, was believed to have injured at the very least 22 folks earlier than that.
Tadamichi Morisaka, a cetology professor at Japan’s Mie University, mentioned the dorsal fin of a dolphin noticed biting a person’s fingers at a seashore in Tsuruga – a port metropolis subsequent to Mihama – matched these of a 2.5m lengthy dolphin noticed off the coast of Fukui province final yr.
The dorsal fin is sort of a dolphin’s fingerprint, as every has distinctive notches, ridges and pigmentation.
“It is affordable to imagine that it’s the similar particular person, as the injuries on the tail fin are much like these of the dolphins seen off the coast final yr, and it’s uncommon for dolphins, which usually transfer in teams, to be alone for such a very long time,” Prof Morisaka instructed NHK.
He added that male bottlenose dolphins talk by “play-biting one another”. “They will not be attempting to injure folks, however are utilizing the dolphins’ manner of communication with folks,” he mentioned.
Others have urged numerous theories on why the identical creature could also be behind these assaults – together with a want for intercourse.
“Bottlenose dolphins are extremely social animals and this sociality may be expressed in very bodily methods,” mentioned Dr Simon Allen, a biologist and principal investigator with the Shark Bay Dolphin Research undertaking.
“Just as in people and different social animals, hormonal fluctuations, sexual frustration or the will to dominate may drive the dolphin to injuring the folks it interacts with. Since they’re such highly effective animals, this may result in severe damage in people.”
Dr Allen added that the dolphin could have been “ostracised from its personal group and be in search of various companionship”.
Dr Matthias Hoffmann-Kuhnt, a marine mammal professional on the National University of Singapore, mentioned the dolphin may be performing in its personal defence.
“Most of the time, in my expertise, that is extra a defensive behaviour when people get to shut to those dolphins and have no idea how you can conduct themselves,” he mentioned, referring to reviews of individuals attempting to experience the animals or sticking their fingers into the dolphins’ blowholes.
“Thus it’s no marvel that the animals then flip aggressive or at the very least protecting towards people within the water,” he mentioned.
It may be that the dolphin beforehand had a nasty encounter with a human being and now tasks that relationship onto different people it encounters, Dr Hoffmann-Kuhnt mentioned.
“They have good reminiscence, much like elephant who will keep in mind who mistreated them earlier than,” he mentioned.
Additional reporting by Chika Nakayama in Tokyo
