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 thus far this yr, with one major school-aged kid’s finger needing at the very least 20 stitches.
At the least six individuals have been injured in assaults final yr, leaving one swimmer with damaged ribs. One other particular person was injured in a 2022 assault.
It has led officers to warn that not solely can the mammals “chunk 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”.
Regardless of their repute as pleasant animals, dolphin assaults will be deadly. In 1994, a dolphin in Brazil attacked two male swimmers who tried to journey it, killing one and injuring the opposite. The dolphin, nicknamed Tião, was believed to have injured at the very least 22 individuals earlier than that.
Tadamichi Morisaka, a cetology professor at Japan’s Mie College, stated the dorsal fin of a dolphin noticed biting a person’s fingers at a seaside 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’s 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 informed NHK.
He added that male bottlenose dolphins talk by “play-biting one another”. “They don’t seem to be attempting to injure individuals, however are utilizing the dolphins’ means of communication with individuals,” he stated.
Others have urged varied 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 will be expressed in very bodily methods,” stated Dr Simon Allen, a biologist and principal investigator with the Shark Bay Dolphin Analysis venture.
“Simply as in people and different social animals, hormonal fluctuations, sexual frustration or the will to dominate may drive the dolphin to injuring the individuals it interacts with. Since they’re such highly effective animals, this could result in severe damage in people.”
Dr Allen added that the dolphin might have been “ostracised from its personal neighborhood and be looking for different companionship”.
Dr Matthias Hoffmann-Kuhnt, a marine mammal knowledgeable on the Nationwide College of Singapore, stated the dolphin is also appearing in its personal defence.
“More often than not, in my expertise, that is extra a defensive behaviour when people get to shut to those dolphins and have no idea the way to conduct themselves,” he stated, referring to studies of individuals attempting to journey 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 stated.
It is also that the dolphin beforehand had a foul encounter with a human being and now tasks that relationship onto different people it encounters, Dr Hoffmann-Kuhnt stated.
“They’ve good reminiscence, much like elephant who will bear in mind who mistreated them earlier than,” he stated.
Further reporting by Chika Nakayama in Tokyo
