More right handedness

In other news, most walruses are right-flippered.

The walrus has been added to the growing list of animals that seem to prefer using one hand, or flipper, over the other. The ivory-tusked sea mammal tends to use its right flipper to forage for clams on the sea bed, say scientists. Anatomical studies confirm that the bones in the walrus’ right limb are longer than those in the left – the same phenomenon seen in right-handed people. The Danish, Swedish and Greenland researchers report their discovery in the online journal BMC Ecology.

Handedness – preferring one side of the body to the other for certain tasks – has been found in chimps, monkeys and even crows, so it is perhaps not surprising that it should be found in an aquatic mammal. Handedness has long been studied in the human population, but, after more than 150 years of research, scientists are still divided over why right-handers vastly outnumber left-handers. It seems to be something to do with the way the brain is organised into two halves, allowing one side to specialise over the other for certain functions such as language.

Some have postulated that handedness arose in primates and is somehow related to the development of speech or tool-making skills. But the latest research casts doubt on this, as did the recent discovery that a species of Pacific crow uses the right side of its beak to craft leaves into tools for catching insects. “Some people say handedness developed in primates from tool manipulations,” lead researcher Nette Levermann, of the University of Copenhagen, told BBC News Online, “but this cannot be the driving force because it is found in walruses and, to a certain extent, in humpback whales and catfish.”

Has anyone found an ambidextrous walrus? A left handed catfish?