For years we have known that the New Caledonian crow used sticks as tools to pry insects and grubs from hard to reach spots. But a recent study of captive Hawaiian crows shows that the skill may not only be more common than previously thought, but also that it may be genetic rather than learned.
Hawaiian crows have been extinct in the wild for almost a generation, but a captive group of them has been observed using sticks to perform the same behavior as their New Caledonian cousins. The researchers isolated young crows to be sure that they had not seen the behavior before, and discovered that without any training, 78% spontaneously picked up sticks and used them to pry food from various crevices in their enclosures.
Tool use is extremely rare among animals. Less than 1% of all species have been shown to use tools in their behavioral repertoire.
The study suggests that tool use among tropical crows might be the result of the specific evolutionary pressures of living on remote islands—pressures like low competition and hidden prey—and that there is something embedded within the crows’ brain that, given the right circumstances, leads to this behavior.
The finding opens up opportunities to study tool-making as a biological event rather than a learned one, which could also offer insight into the development of tool making and tool use in primates, including humans. Tool use is a poorly understood part of our evolutionary past. Indeed, it could very well be one of the great achievements of human society, evolving as it has from the hand axe to the power drill to the iphone, let alone the inflatable pillow tie. Knowing how the knack for tool use came about would make a valuable contribution to our understanding of our evolutionary history.