New Caledonian Crows Mentally Represent Metatool Problems

One of the mysteries of animal problem solving is the extent to which animals mentally represent problems in their minds. Humans can imagine both the solution to a problem and the stages along the way, such as when we plan one or two moves ahead in chess. The extent to which other animals can do the same is far less clear. Here, we presented New Caledonian crows with a series of metatool problems where each stage was out-of-sight of the others and the crows had to avoid either a distractor apparatus containing a non-functional tool or a non-functional apparatus containing a functional tool. Crows were able to mentally represent the sub-goals and goals of metatool problems: crows kept in mind the location and identities of out-of-sight tools and apparatuses while planning and performing a 3-stage sequence of tool behaviours. This provides the first conclusive evidence that birds can plan several moves ahead while using tools.