walruses no southpaws

Joining the ranks of animals like humans and monkeys, walruses have been found to be mostly right-handed. The walrus prefers using its right flipper over its left one when foraging underwater for food buried in mud on the sea bed. A team of scuba-diving researchers from Denmark, Sweden, and Greenland filmed the animals digging for clams, a favorite food, and reported the discovery last week in the online journal, BMC Ecology. The videotapes revealed that the walruses had various other foraging methods, but using their flippers was the most-popular technique by far, being used 70 percent of the time. And when only flipper-use was considered, it was found that the right flipper was used 89 percent of the time. Anatomical studies of walrus skeletons in collections confirmed that the bones in their right limbs are longer than those in their left, an effect also seen in right-handed humans and that probably develops due to greater use of the right limb. “The implication of these findings,” the team stated, “suggest that tool use and object manipulation is not mandatory for the development of strong limb preferences or handedness.”

This news brief appeared in the Random Data column of the Boston Globe’s Health/Science section on 10/28/2003.