Wednesday, May 19, 2010


An analysis of dolphin interventions in shark attacks on humans concludes that dolphins have less than honorable motives.

Dolphins have earned a reputation for protecting humans from shark attacks, is this reputation deserved or has their behaviour been misinterpreted?

Typically the story goes something like this: The human(s) are either injured by or uncomfortably close to a shark when dolphins come to the rescue. They circle the human(s) and, while beating their tails on the water to repel the shark, they drive the human(s) towards the shore.

One explanation for the dolphins’ behaviour is that they are altruistically putting their lives at risk to save humans from their natural enemy, the shark. They do this by using behaviours very similar to their natural hunting behaviours while at the same time, misguidedly attracting the shark!

A much more plausible explanation is that dolphins are using what they know about herding and corralling prey to drive the human(s) to, or to keep the human(s) in a vulnerable position, while attempting to attract the shark. Should the shark prove too dangerous to be driven off by the dolphins, they can make their escape - leaving a largely helpless human to distract the shark and possibly sate its hunger.

In one widely reported event a shark had three attempts at trying to consume surfer Todd Endris, causing him severe injuries. Then dolphins that had been in the area came along to circle him, supposedly keeping the shark at bay until he could catch a wave into shore.

From this account we can assume that the shark wasn’t actually big enough to consume Todd or even kill him without repeated attacks; Putting it at a size within the realm of threatening to dolphins but defendable at considerable risk.

In another widely reported event a group of swimmers in New Zealand were surrounded by dolphins, the dolphins were circling them and slapping their tails in the water. One swimmer then noticed a shark close by in the clear water. The dolphins continued to circle the swimmers, slapping their tails on the water until the shark ‘lost interest’, then the swimmers swam back to shore with the dolphins close behind.

This shark was only big enough to be noticed by one of the swimmers.

Shark and dolphin interactions in the wild are quite common; usually it involves a large shark eating a smaller dolphin. Dolphins will attack some shark species if the shark is small enough for the dolphin to stand a fighting chance, to protect their young or if they are left with no other avenue of escape. In other cases, self-preservation seems to feature highly and they do their best to get out of the area as quickly as possible.

Wild dolphins are known to herd groups of fish by circling them and driving them into a compact mass, making them easier to catch. Corralling is another behaviour commonly exhibited by wild dolphins were groups of fish are driven into shallow water, again making them easier to catch.

As for tail slapping, sharks are attracted to noise in general and especially to such noises as slapping on water. Some Pacific Islanders build ‘rattles’ from coconut shells and shake them up and down at the waterline specifically to attract sharks.

So next time you’re out swimming and dolphins start circling - save your romantic notions of inspirational interspecific interactions with those dastardly dolphinian dealers in death until you get OUT OF THE WATER - because those dolphins are smarter than we thought.

All comments containing the word spiritual, healing or using the word vibration to refer to something that isn’t actually vibrating will be automatically deleted.


Tom said...

Yes. Dolphins want to kill us all. Run! Run for the hills.

Swim with them and you'll see just how fearsome and conniving they really are.

Troy said...

Your theory sounds plausible, however, I dont think Dolphins are quite that self serving. Especially considering there extremely curious and loving nature. Also, Just curious Chris, why is it you will delete any comment with the words spiritual, healing, or vibrating? Although I don't quite follow the purpose of vibrating statement. And please, don't misunderstand me as being sarcastic or condescending either. Just that I would really like to know?

Chris said...

Hi Troy and thanks for your comment.
I just wanted to steer the comments left here towards a scientific rather than a metaphysical basis as
the article is about animal behaviour.