SNOWBIRD, UTAH--Even killer whales have domestic squabbles, at least in captivity. And a new study suggests that, like humans, the whales often reconcile their differences, in their case with some side-by-side swimming. The finding suggests that reconciliation isn't a behavior unique to big-brained primates.
Human relationships undoubtedly benefit from peacemaking skills, and many studies have shown that the same is true for chimpanzees, other primates, and perhaps even hyenas. Yet the ability to reconcile has never before been identified in marine mammals. The new evidence comes from 2800 hours of killer whale videotape recorded at MarineLand in Niagara Falls, Ontario, by animal behaviorist Michael Noonan of Canisius College in Buffalo, New York.
Although aggressive behavior between the whales is extremely rare, Noonan and colleagues identified 21 brief spats. Many of these involved several whales and were complicated interactions, but eight of them were unambiguous quarrels between a father and a mother. Each time, mom chased her partner, who would flee and occasionally perform a sort of cartwheel to evade her. This would continue intermittently for several minutes, after which the two would separate for a cooling off period, typically around 10 minutes.
But then, instead of simply going about their business once the tension had subsided, the pair would swim synchronously, side by side, in an apparent display of togetherness. Known as parallel or echelon swimming, the reunion would last another 10 minutes or more before life in the tank returned to normal, Noonan reported here 15 August at the Animal Behavior Society meeting. Although he admits that this ritualized togetherness doesn't prove the whales are reconciling, he says it's strongly suggestive of peacemaking.
James Ha of the University of Washington in Seattle agrees, but he cautions that wild orcas apparently don't squabble with their relatives. On the other hand, conflicts between pods commonly lead to echelon swimming, which seems to calm the group and reinforce social bonds. "What these animals in captivity have done is switched the use of the behavior." Even though the use of parallel swimming to mend fences may be an artifact of captivity, it could indicate that other species, including humans, have also adapted social bonding behavior to resolve conflict. "It may give us a little idea about the evolution of reconciliation," Ha says.