It's not unusal for bottlenose dolphins to attack harbour porpoises, it's something we've known about for years and is often their largest cause of death here in the UK. I wanted to put the link up for this as I know it's not very commonly known about outside scientific cetacean research circles and also as it's very rare to get pictures.
It had two badly broken jawbones, fractured ribs on both sides and a broken scapula, evidence of a sadistic attack. Worst of all, the female porpoise, which had been seen twice before and identified by researchers in Monterey Bay, was lactating when she was killed, according to marine biologists.
It was a clear case of what scientists are calling "porpicide," the deliberate slaying of a harbor porpoise by a surprising and, to most people, unlikely culprit.
"We suspect that it was a bottlenose dolphin," said Bill Keener, a researcher for Golden Gate Cetacean Research.
The brutal battering wasn't an isolated incident. Scientists say there has been a dramatic increase in dolphin attacks on harbor porpoises along the California coast over the past few years, including an attack Wednesday off Half Moon Bay.
Read more: http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2011/09/16/BADK1L3JVQ.DTL#ixzz1YOpvZF00