Living World / Unusual Organisms

Seals are Guided by Voices Seals seem to be smart enough to master a foreign language when they need to. Volker Deecke, a marine biologist from Scotland's St. Andrews University, played killer-whale calls to wild Pacific harbor seals in the coastal waters of British Columbia. Many killer whales eat seals; others stick to a fishy diet. The seals panicked when they heard unknown orcas or known seal eaters but stayed calm when confronted with the familiar calls of killer whales they knew to eat only fish.

Deecke suggests that seals' ability to recognize whale voices might explain the long-standing puzzle of why Pacific killer whales fall into two such distinct populations, fish eaters and seal eaters. Seals are a rich food source, but they are quickly scared off by whale calls. One population may specialize in hunting fish, Deecke says, because although fish require more effort to catch, they cannot hear whale calls. The other population seems to have settled on a strategy of hunting seals by remaining silent. Seals, in turn, have learned to tell which type of prey each whale prefers. "Dolphins and whales are intelligent, but seals are capable of distinguishing nuances and complexities of another species. In a way, that's even more impressive," Deecke says.