Dolphins are bastards, apparently.

Unusual suspects - 31 July 1999 - New Scientist:

"...Richard Connor and his team from the University of Massachusetts, Dartmouth, have spent more than a decade watching dolphins in Shark Bay, Western Australia. They were the first to notice that mature males tend to hang out in pairs or trios when consorting with females. The bond between such gang members is as strong as that between a mother and her calves, and stronger than any other social interaction among members of this 400-strong group. What is going on?

Connor soon realised that these male gangs were after just one thing: sex. A trio—let's call them the Sharks—will kidnap a sexually receptive female from her normal group and hold her prisoner for a month or more. There is no gentle courtship. Instead the Sharks herd their trophy around, using brute force including thumping and biting to keep her moving where they want. Meanwhile they mate with her, either one at a time or sometimes simultaneously..."

While you contemplate dolphin rape gangs, don't forget the serial killers.

New Scientist Environment Blog: Dolphin serial killers?:

"Scientists who autopsy cetaceans that wash up dead on British beaches have come to a grim conclusion: some species are being killed by bottlenose dolphins.

Dead porpoises (and other cetaceans) turn up regularly on beaches around Britain. According to a Defra report last year (pdf), the cause of death of 15 out of 56 porpoise bodies found - the majority - was "physical trauma (bottlenose dolphin attack)". The photo above shows the rake marks on a harbour porpoise caused by a bottlenose dolphin.

..."We can't state confidently that the killings are tied to declining fish stocks," says dolphin expert Nick Tregenza, who advises the Marine Strandings Network in Cornwall. His guess? "They could be doing it for fun.""