October 12, 2011 Featured Article Read More →

Do Porbeagles Play?

Porgie (C)The Porbeagle (Lamna nasus) has all the hallmarks of an aggressive predatory shark: a powerful, stocky body, dark menacing eyes and jaws that hold up to 30 rows of razor sharp teeth. However some scientists and anglers have observed unusual behaviour in Porbeagles that seems to contradict their sometimes sinister appearance. Porbeagle sharks have apparently been observed “playing”.

Play is a notoriously difficult activity to define when it comes to the animal kingdom, many animals – and in particular juveniles – play in order to develop social and cognitive skills that will be invaluable later in life. However, play has generally been restricted to mammals and birds making it all the more remarkable that Porbeagles seem display play behaviour.

Groups of juvenile Porbeagles have been observed repeatedly rolling amongst kelp fronds near the surface until they are tangled in the algae before darting away trailing the fronds behind them. In response, other members of the group were said to chase the kelp-covered shark biting at the kelp fronds before the activity was repeated.

The repetitive nature of this activity is seen as key to defining it as play behaviour. Possible explanations for the behaviour have been proposed including that the sharks were attempting to feed on small organisms attached to the algae or were attempting to use the tough fronds to remove parasites from their own body. However these explanations were deemed unlikely by the scientists who witnessed the event and it was said that the sharks “appeared to engage in these activities for no apparent reason other than to pass time”. In other words the sharks appeared to be playing.

Juvenile Porbeagle sharks have been seen chasing each other in a manner described as “strikingly similar to dolphins” with no apparent motives other than to have fun! It is possible that play behaviour in Porbeagles may play an important role in developing young sharks into effective predators as seen in many mammals.

Porbeagle sharks have also been observed interacting with floating objects to an extent beyond that which would be seen as investigatory behaviour. Groups of up to 20 Porbeagles have been seen manipulating floating objects including driftwood, seaweed and anglers floats and the sharks have been observed passing objects from one individual to another and repeatedly tossing the objects clear of the water. Once again the repeated and seemingly pointless nature of this behaviour is said to be “characteristic of what would unhesitantly be termed play in other animals”.

It cannot currently be determined whether or not Porbeagles play or whether the behaviour serves an underlying purpose; some of the scientists studying the sharks stated that “the best way to identify play is to witness it!” and remain adamant that the sharks were indeed playing.

Playing is often seen as a sign of high intelligence in animals and is notoriously difficult to define or identify and as such many experts have been reluctant to accept the Porbeagles behaviour as play. The alternative explanations offered for the shark’s behaviour have been deemed equally remarkable in their own right and show a level of intelligence, object manipulation and self awareness rarely seen in fish species.

The issue of whether animals play or not can seem trivial though there is no denying the fact that such behaviour can significantly alter the human perception of a species. Regardless of whether or not the behaviour witnessed in Porbeagles is what humans would regard as “playing” this work does point towards a level of intelligence rarely seen in elasmobranchs.

Posted in: Shark Bites
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