Bottlenose Dolphin: The Only Marine Animal that Kills for Fun

This may seem hard to believe, but the adorable dolphins you swim with at Sea World may not be as innocent as you think. According to marine experts, the bottlenose dolphin might actually be the only animal on earth that murders fellow underwater inhabitants for the sheer fun of the kill.

The first clues arrived in 1997, when a succession of dead porpoises were washed up in the waters of Scotland’s east coast and the shores of Virginia. Biologists found that the porpoises had died of broken ribs, damaged livers, and imploded lungs, which served as tell-tale signs of prolonged, focused attacks. Although the motives were unclear, the teeth marks discovered on the bodies were a sure-fire sign: the prime suspects of these murders were bottlenose dolphins.

DolphinsPhoto: Nick Ares

Some scientists have theorized the dolphins kill to protect their way of life. Typically, an animal will instinctively attack other animals for the sake of defense, territory or food. However, what makes this particular case questionable is that food supply is not short. What’s more, the dolphins hunt and kill the intruding porpoise rather than chasing it away, providing further reason to believe the motives are malicious rather than instinctual.

The murders were confirmed by a film that surfaced, which depicted a group of bottlenose dolphins attacking a porpoise to the point of breaking its back and shattering its soft tissue. More shocking footage of this behavior can be found in the English documentary program, The Dolphin Murders. It is believed that these violent tendencies have always been present but have only come to notice recently due to dolphins’ human-friendly behavior, allowing them closer contact with tourist boats and beaches.

In an even more shocking discovery, young dolphin corpses with matching injuries were spotted on the same shores as those where the porpoises were found. The reasons why bottlenose dolphins kill their young are unknown. However, some scientists believe it is due to mating instincts. In the wild, a lion will kill the young in order to make the mother available to mate again. Some researchers say the same principles may apply for the bottlenose dolphins. However, proof has shown the killing of young dolphins is not restricted to the male population, which only makes the case more perplexing.


Perhaps we’ll never know why bottlenose dolphins kill the porpoise or its young. It could be instincts, or they could merely enjoy the process. One thing is for certain: you’ll never look at a bottlenose dolphin the same way again!