A porpoise was killed earlier this week after being flung from the sea by a dolphin in Newlyn Harbour in Cornwall, England. Though marine biologists can’t say for certain what drove the battling bottlenose to attack the ill-fated creature, the Cornwall Wildlife Trust (CWT) told BBC News that the assault may be a case of “misdirected sexual aggression.”
Photographs of the marine mammal mayhem were captured by rowers Lizzie Warner and Sue Nankervis of the Pendeen Pilot Gig Club, who happened to be out on the water when the violent incident occurred.
The CWT says that while there a number of possible motivations for the attack, predation is definitely not one of them: “Many theories have been put forward, including misdirected infanticide (bottlenoses will kill calves), misdirected sexual aggression or play behavior and an aggressive response to feed competition are just some.”
The porpoise's body was later found with multiple severe injuries. Sue Nankervis & Lizzie Warner of Pendeen Gig Club
It also said that such attacks are rare but by no means unheard of, with about one porpoise a year being killed by dolphins.
The tactic of launching animals out of the water in order to kill them has previously been employed by other marine mammals elsewhere. Patagonian orcas, for example, were recently observed trying out a new hunting method, whereby a pod chased a dolphin into the path of a killer whale hiding in the depths, which then headbutted it from below with such force that it flew 5 meters (16 feet) out of the water.
Clearly, this mode of attack is highly effective, as the Marine Strandings Network, which found the dead porpoise, described it as riddled with “multiple severe injuries.”