Study says many sharks get along swimmingly
Jaws, the movie, has a lot to answer for.
Of all the creatures in the animal kingdom, a shark is the one that just about everybody is likely to avoid. But of the 400 or so shark species swimming in the oceans, just three or four attack humans.
And now a study suggests that, in fact, sharks have complex personalities, and many of them are surprisingly sociable. The University of Exeter research appears to prove that sociability between sharks varies enormously, and is not determined by the species or where they happen to live.
The study analyzed 10 groups of 10 small spotted catsharks, monitoring their interaction in three environments. It showed that some sharks — regardless of environment — enjoy each other’s company, congregating in groups and sometimes lying on top of each other to rest.
But other sharks were loners, staying away from any group.
The study adds to a body of work that shows animals display not just character traits, but individual personalities, and possibly even emotion, too.
This might seem implausible. Personality, by definition, is something only people possess. Are generations of scientists brought up on Disney films over-anthropomorphizing?
William Hughes, an animal behaviour expert at the University of Sussex, says: “Personality is just a term used. We’re not talking about animals having human personality traits. What we mean by animal personality is consistency of individual behavioural traits over time and across contexts.
“In the past 10 years, there has been a minor revolution in the work of animal personality.”
He says the shark study was a detailed look at their behaviour over a long period of time; an experiment comparable to watching a group of people. “Imagine if we took 10 work colleagues and placed them in a bar, and observed which individuals sat with which other individuals over the course of an evening. Then you did the same thing in a nightclub and in the work environment.”
It would appear that some small spotted catsharks, which have the appearance of supersized tadpoles, like to hang out with their friends. Others, bless them, just want some peace and quiet away from the dance floor.
A similar experiment by Jean Sebastien Finger, a biologist in the Bahamas, monitored lemon sharks and found that while some were novelty seekers, others were less keen to explore. “They are not machines, they have personalities,” Finger said.
Hughes adds that scientists are increasingly confident that animals, from insects to primates, display complex personalities.
The University of Bordeaux, for instance, found that freshwater crayfish display anxiety, hiding in dark corners of a tank, rather than brightly lit parts. Brown trout also display shyness.
The “loner” sharks in the study appear to behave this way to protect themselves from predators — hoping they will not be spotted hiding on the sea bed. Hughes says: “This is the million-dollar question. We know environment must affect personality.
“But figuring it out to what extent, and how much the strength of the personality is genetics and how much is environment, is the next area of study.”