Observational evidence has long suggested that elephants are pretty smart; they can mimic sounds they hear, they have elaborate death rituals, and they can rock out on the harmonica. However, due to their sheer size and their frightening ability to crush a skull with one stomp of their foot, little experimental research has been done on their cognitive skills. Now, a new study in PNAS shows that elephants know when they need help, and they also understand the role of a partner in cooperative tasks.

The researchers studied 12 elephants at the Thai Elephant Conservation Center in Lampang, Thailand, and modified a task that has been used in cooperation research in several other species. A sliding table carrying two food bowls could be moved only by pulling both ends of a rope that was threaded through two pullies. If only one end of the rope was pulled, the rope became unthreaded and the table would not move. This apparatus was placed behind a transparent barrier (a volleyball net) so that the elephants could see the set-up but couldn’t reach the food. The elephants were released into two different lanes on the other side of the net, with one end of the rope lying in each lane.

First, using a simpler apparatus, the elephants were trained to pull a rope attached to a food bowl. Then, the experiment began. In the first stage, two elephants were released into the lanes at the same time. The elephants quickly learned that they needed to synchronize their pulling of the ropes to attain the food reward. However, this doesn’t say much about cooperation, since the elephants may have just been adapting their “see rope, pull rope, get food” knowledge from the training period. To determine whether the elephants actually understood the cooperative nature of the task, the researchers then modified the experiment slightly.

In this stage, one elephant was released into the lane with a head start; the second elephant was released five seconds later. In order to succeed at this task, the first elephant to be released needed to recognize the need for a partner, and had to wait to pull until the second elephant was able to help. Once the pair had successfully completed the task three times in a row, the head start was increased to 10 seconds, then 15, all the way to 25 seconds.

The total number of trials that the pair required to reach the 25-second mark was then tallied. All the elephant pairs completed this stage in 30 trials or fewer (a “perfect” score, if the elephants had made no mistakes at all, would have been 15 trials). Individual elephants made between three and six errors during this stage; in a study with a similar setup, chimpanzees made up to 28 errors.

Interestingly, some of the elephants adopted slightly different strategies from the rest. For example, Instead of pulling, one young female simply put her foot on her end of the rope. Her partner then arrived and pulled, retrieving the food without the young female doing any extra work at all. Another elephant waited for his partner at the release point, rather than at the apparatus. Alternative strategies such as these are often cited as examples of creativity and advanced intelligence.

These results show that not only can elephants learn to complete cooperative tasks, they understand the role of a partner in these tasks, and they understand that the task cannot be completed if their partner cannot act. Experiments with corvids, hyenas, and capuchin monkeys showed that these species either failed to complete the task, or left questions as to whether or not the animals understood the role of their partner. While there is still much left to figure out, elephants may rival apes in their ability to perform and understand cooperative tasks.

PNAS, 2010. DOI: 10.1073/pnas.1101765108 (About DOIs).