Something to chew on. I like the part about fat ones near shore and sleeker faster ones in the middle of a lake. Kinda like some of the stages in life.
Fishy quirks include risk-taking, study finds
Personalities evident in trout, Ontario researcher finds
Tom Spears
CanWest News Service
Monday, November 26, 2007
OTTAWA -- Fish have personalities.
Ordinary Canadian brook trout exhibit different traits: some are social, others not. Some are risk-takers, others scaredy-fish. And so on.
University of Guelph scientists noticed the different personalities as they sat by the Credit River, west of Toronto, watching trout feed. Then they scooped out the fish and ran them through six days of personality tests in the lab, and even some swimming tests.
And the revelation suggests an answer to an old question: How can different species, with different types of behaviour, evolve from a single starting point?
The idea of personalities is starting to spread across our views of the whole animal kingdom, says Rob McLaughlin, the Guelph biologist who ran the study. This seems obvious in the case of dogs or chimpanzees, but less obvious among fish.
"We've known that out in the field, these young brook trout examine differences in their foraging behaviour -- what they're feeding on," he said.
In many lakes and rivers, there are two visibly different subgroups of the same fish species -- a slower and fatter version near shore and a sleeker, faster one out in open waters.
But the Credit River brookies haven't reached that stage. They all looked the same, all living in a pool together, yet showing behaviour that differed. Some slower trout stayed near shore and hunted for tiny crustaceans while others rushed around in deeper water, picking insects off the surface.
McLaughlin and student Alex Wilson found that the personalities of the fish that went to the Guelph aquarium for tests stayed distinct even after the young fish, still just two to four centimetres long, left their natural homes.
For instance, he put the fish in a dark tube in the aquarium. The more active fish were always the ones that emerged into the main body of the tank first. They were more ready to take risks, and less afraid of unfamiliar objects in the water.
"What they do in the field predicts what they do in the lab," he said.
"We were getting this sense that they perceive the environment differently, and the kind of things we measured are part of what people are starting to call personality traits in animals."
Most studies on species that subdivide focus on groups that have already split from each other, he said.
"We were interested in, how does it get started in the first place? There's this idea that you have these behaviourally flexible animals and they have an environment with different food types or habitats," and gradually they specialize to focus on one food type or habitat.
The study was published in a science journal called Animal Behaviour.
"The recognition that behavioural syndromes exist in a wide range of animal species is a key development in the understanding of animal behaviour," the journal says in an editorial.
"The significance of these findings, and of other studies dealing with behavioural syndromes, is that we cannot assume that all animals in a population fit into precisely the same niche, or that they will all show the same degree of flexibility."
© The Vancouver Sun 2007
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