Japan on high alert. The reason? A lonely, possibly sexually frustrated dolphin

Dolphins are generally considered friendly, but the increase in attacks has prompted warnings of the potential danger. Local authorities said: “They can bite you with their sharp teeth and make you bleed, or drag you into the sea, which can be life-threatening.”

Although dolphin attacks are rare, they can be fatal. In 1994, a dolphin named Tião was responsible for the death of one swimmer and the serious injury of another in Brazil after he attempted to ride the animal. Experts believe Tião had previously injured at least 22 people.

The dolphin responsible for the recent attacks in Mihama, Japan, was identified by its distinctive dorsal fin, which has unique notches and pigmentation. Tadamichi Morisaka, a cetacean professor at Japan's Mie University, noted that the same dolphin was spotted off the coast of Fukui Province last year. “It is reasonable to assume that this is the same individual, as the wounds on the tail fin are similar to those spotted off the coast last year,” he said. He explained that dolphins, known for traveling in groups, rarely stay alone for long periods of time.

Morisaka suspects that the dolphin may be demonstrating “playful biting,” a natural behavior of male bottlenose dolphins, and that it may not intend to harm humans. He said: “It is reasonable to assume that this is the same individual, as the wounds on the tail fin are similar to those seen offshore last year.” This could mean that the dolphin is trying to interact in the only way it knows how.

Dr. Simon Allen, a biologist with the Shark Bay Dolphin Research Project, noted that hormonal changes or social isolation could be the cause of the dolphins' aggressive behavior. “Because they are such powerful animals, this can cause serious injury to humans,” Dr. Allen said. He pointed out that the physical strength of these mammals makes their actions dangerous despite their intentions. Marine mammal expert Dr. Matthias Hoffmann-Kuhnt suggested that the dolphin may react defensively when humans get too close or attempt inappropriate interactions. He also suggested that a negative experience with a human in the past could cause the aggressive reactions. “They have a good memory, similar to elephants who remember who has mistreated them before,” he said. This highlights dolphins' ability for long-term memory, which influences their behavior.