By Susan Milius
In a test of cooperation, elephants know when two trunks are better than one.
Working in pairs, elephants learned to pull on the same rope at the same time to haul tasty corn within reach, says comparative psychologist Joshua Plotnik, now at the University of Cambridge in England. The animals didn’t just learn a trick by rote, he says, but rather showed signs of grasping the basics of how cooperation works.
For example, elephants alone at the snack site learned not to pull at the rope or leave before their partners arrived up to 45 seconds later to help with the task, Plotnik and his colleagues report online March 7 in the Proceedings of the National Academy of Sciences. “That’s a long time for an animal waiting for food,” he says.