Do Asian elephants plan for mutually-exclusive outcomes?

Abstract The ability to prepare for mutually-exclusive outcomes is critical for future planning. Recently, the thought that this ability may be unique to humans has been questioned. Even if non-human animals cannot individually plan for mutually-exclusive outcomes, groups of individuals may be able to coordinate their behavior to do so collectively. Here, we tested 12 Asian elephants (Elephas maximus), both individually and in pairs, using a forked tube task—adapted from one used with children and non-human apes—where a food reward is dropped down a tube and exits from one of two openings. The consistent, simultaneous covering of both openings to obtain the reward is evidence of an understanding of mutually-exclusive outcomes. One elephant—Nammei—learned to manipulate her trunk in a scooping motion to autonomously cover both openings, and then performed this behavior relatively consistently to successfully obtain the food reward at a rate significantly greater than chance (61.5%). In addition, pairs of elephants obtained the food reward at a rate significantly greater than that at which individuals could do by chance (i.e., either elephant ate the food in 60.1% of pair trials). However, Nammei eventually reverted to covering only one opening, and pairs did not achieve complete coordination—in fact, both openings were covered in only 35.0% of pair trials. Therefore, our results fall short of providing compelling evidence for either individual or collective planning for mutually-exclusive outcomes in elephants. However, the interesting behaviors that we observed suggest that this is a promising area for future research.