Teenage Murderers

Enjoy a new feature here at jimcofer.com: the Science Blog! When researching posts for the History Blog, I often come across things that interest me, but aren’t really “history”, so to speak. When I heard about the following story, I knew I just had to post it, but doing so would require a new category… and thus, the Science Blog was born!

It sounds like an urban legend about gang initiations: teenage males come together to form a pack, pick out a random victim, form a circle around him or her, then beat the victim to death… just for thrills. Sadly, however, it’s not an urban legend. It’s very real. But what might surprise you is who is doing this. It’s not inner-city gang members looking for “street cred”. It’s not packs of skinheads looking for an immigrant to beat up on. It’s not even drunken hicks looking for a gay guy to bash on. No. The perpetrators in this case are… bottlenose dolphins.

Modern American culture holds dolphins in high regard. And why not? They’re beautiful creatures. They’re highly intelligent. And it seems that, in many cases, dolphins like us. I’m sure you’ve heard stories of a pack of dolphins carrying a drowning man to the shore, or a pack of dolphins saving a diver from a shark attack. Since at least 1964 (when the TV series Flipper debuted), most Americans have thought of dolphins as friendly little sea creatures almost as smart as ourselves.

In the summer of 1997, however, marine biologists in Virginia and Scotland began finding the bodies of young bottlenose dolphins washed up on the beach. The bodies were in horrific shape, and the biologists initially blamed the deaths on the U.S. Navy (in the Virginia case) and an offshore oil rig (in the Scottish case).

The biologists quickly changed their tune after the young dolphins were autopsied. Their internal organs had been pulverized while the tissue surrounding the organs was left intact. What’s more, the internal organs appeared to be injured in order of their importance to the young dolphin – their hearts were almost completely destroyed, while their stomachs (while still perhaps fatally injured) where in much better shape, relatively speaking. These factors immediately ruled out any type of “shock blast” from the Navy or the oil rig, as any such blast from those sources would have injured the dolphins’ organs equally. The biologists would remain stumped until the smoking gun finally appeared: some of the researchers – who were now working together on both sides of the Atlantic – were able to definitively show that the victims had teeth marks from their fellow dolphins.

All this was confirmed as home video of “dolphin murders” started to make its way into the hands of the researchers. Several vacationers, on day trips to view dolphins or whales, began recording amazing footage of packs of dolphins isolating a baby, beating it to death, then playing with the corpse (much as a cat might play with a dead mouse).

The big question here is, of course, why the dolphins kill some of their young. The dolphins never eat their victims, nor is food lacking in the areas where the murders occur, so hunger cannot be the cause. Most of the victims appear to have been in good health before the beatings, so it does not appear to be a “kill the weaker so that the rest may survive” situation. Most of the victims are members of the murderers’ “family”, so it does not appear to be an issue of territory (especially since most animals, dolphins included, will simply chase any unwanted animals out of their territory instead of killing them). Some have speculated that it’s somehow about mating, since once a calf dies, a female dolphin is ready to mate again; this seems quite illogical (“Let’s kill your baby so we can make a baby!”) and scientists aren’t completely sure that it’s only males that take part in the murders.

The most popular (and obvious) hypothesis is that the young male dolphins are using the young calves – which are usually around the same size and age, by the way – as a type of “target practice”. After all, those young males may one day be called upon to defend the pod against an attacker. But that doesn’t explain the sheer brutality of the attacks, nor does it explain why the dolphins play with the corpses of the victims, often tossing it back and forth to each other like a soccer ball. However, this hypothesis might explain one of the more horrific aspects of the killings: the attackers use their ultrasonic capabilities to hone in on the victim’s vital organs!

Perhaps the greatest puzzle of all is why it only happens off the coast of Virginia and Scotland. Bottlenose dolphins are everywhere in the Atlantic, yet this bizarre behavior has only been spotted in those two places.

There probably is some reason why some dolphins kill their young. But until then, there are now two species on this planet that kill just for fun: man… and dolphins!