Jennifer Viegas, Discovery News
July 23, 2009 -- Female domestic cats tend to preferentially use their right front paw while male cats more often rely upon their left front paw, according to a new study that suggests the sex of a cat determines how its brain will be wired.
The findings also add to a growing body of evidence that male animals tend to be left-handed, or in this case left-pawed, more often than females. While 90 percent of all humans are right-handed, of the remaining southpaws, more tend to be men.
The differences are even clearer among cats.
"Our results suggest that there are two distinct populations of paw preference in the cat that cluster very strongly around the animals' sex," Deborah Wells, who led the study, told Discovery News.
Wells, a senior lecturer at Queen's University Belfast School of Psychology, and co-author Sarah Millsopp examined the paw use of 42 domestic cats. Each cat repeatedly completed three play-like tasks while at home with their owners.
For the first task, the researchers placed a bit of tuna at the bottom of an otherwise empty, narrow-mouthed jar. They then observed how the cats attempted to extract the food treat.
Task two involved a fabric mouse on a string that was suspended above each cat's head. The paw that was first used to reach for the toy was recorded.
Finally, the scientists took the same toy for task two and slowly dragged it on the ground in front of the cats. Again, the first paw used by the cats to try to grab the toy was recorded. In total, the researchers documented 100 paw responses per feline per task.
While the cats did not favor a certain paw for tasks two and three, the paw preferences were very obvious for the tuna-in-a-jar puzzle. The study findings have been accepted for publication in the journal Animal Behavior.
"I think much depends on the task and challenge on offer," Wells explained. "On some challenges, cats may well use either paw, but on others -- perhaps those that are more complex in nature -- some individuals may well have a preference for one paw over another."
In humans, the steroid hormone testosterone has been linked to left-handedness. This hormonal link also appears to carry over to animals. For example, studies on dogs that haven't been spayed or neutered show the same sex-based split, with female dogs favoring their front right paw and males favoring their left. No sex difference, however, was observed during tests involving neutered dogs.
It is unclear how such preferences benefit males and females, but Wells said cats "differ in their behavioral patterns, for example in hunting styles and parental care, and it is possible that these place different demands on motor functioning."
When gesturing to a dog or child under three, it's therefore best not to fidget or otherwise move in confusing ways.
Other research suggests that each of the brain's hemispheres is specialized for approach and withdrawal processes, indicating that the right and left hand sides of the brain control different emotions.
For example, Angelo Quaranta of the University of Bari and colleagues studied how dogs wag their tails and found that when dogs are happy and see something they want to approach, their tail wags to the right. When they are frightened and want to run away, their tails wag to the left.
"Overall, this pattern of results fits with the general hypothesis that there is a fundamental asymmetry in the control of functions related to emotion," concluded Quaranta and his team.
Dog owners might consider observing their own pet's tail-wagging to see if the theory holds true. Wells said cat owners can also try the jarred treat experiment at home to see if their feline follows the documented paw-favoring trends.
"This would be pretty straightforward to do," she said. "The key thing is ensuring the jar is positioned right at the center of the cat, and that not too many trials are carried out at once, otherwise we might just be seeing a reinforcement effect."
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We have not found a cure for cancer but now we know what paw cats prefer. I'm relieved to hear!!
