Just like the intelligent, trunk-nosed mulefa in Philip Pullman's His Dark Materials series, elephants are capable of cooperating in situations where more than one prehensile limb is required. In a series of experiments (pictured here), scientists observed elephants pulling on opposite ends of a rope, cooperating to slide food toward them. Not only did they learn to coordinate quickly, but if their partner was delayed, they'd hold onto the rope and wait to pull until the other arrived. If their partner couldn't get to the rope, they wouldn't even bother. It would seem that elephants, like chimps and humans, understand cooperation beyond simply being trained to act together.
Research published in PNAS
Image via AP