We have posted about orcas attacking and even sinking sailboats off the Iberian peninsula. Recently, we posted about a surfboard-stealing otter.  Now, officials say that four swimmers were injured in dolphin attacks on a beach in central Japan.

The BBC reports that one man, in his 60s, suffered broken ribs and bites to his hands after a dolphin rammed him a few meters off Suishohama beach in the town of Mihama, Fukui prefecture, early on Sunday.

Another man, in his 40s, sustained arm bites in a separate incident on the popular beach the same morning.

Two more people were injured by the mammals later in the day. Fukui has now recorded six such attacks this year, local police say. Signs have been put up telling swimmers to avoid approaching or touching the mammals.
 
While dolphins are not usually aggressive to humans, hostility towards swimmers is not unheard of.

Scientists have suggested that wild bottlenose dolphins find swimming alongside humans “incredibly stressful,” finding evidence that it disrupts their behavioral routines.

Thanks to Alaric Bond for contributing to this post.