Bird-brained and brilliant: discovering New Caledonia's crafty crows
The question of human uniqueness has long been debated, and the defining characteristics of 'human-ness' have been sought by philosophers and anthropologists alike. One such characteristic was once thought to be tool-use: surely no other creature possesses the intelligence to manufacture and manipulate tools?Wrong! We now know that a variety of species use tools; some even manufacture them. The sight of a chimpanzee performing such a human-like action rarely fails to fascinate, but perhaps their proficiency is unsurprising, given our close evolutionary history. More surprising is that the chimps are facing competition from the most unlikely of sources: a bird.
In 1996 it was discovered that a species of crow, native to the small islands of New Caledonia, not only used tools to forage for larvae, but also made them. Since then, New Caledonian crows have shot into the scientific limelight, fascinating researchers and the public alike with the frequency and complexity of their tool-oriented behaviour.
It is in captivity, however, that these crows have revealed the full extent of their tool-making abilities. In one experiment, a female ('Betty') was being tested to see whether she could choose between two pieces of metal wire, one straight and one hooked, to pull up a small bucket of food from a well. Unfortunately, her mate ('Abel') stole the correct, hooked piece of wire. Betty had a go with the straight wire which was left. Unsurprisingly, she failed. But then she stunned the watching scientistsby bending the wire into a hook and retrieving the bucket. Amazingly, she had never encountered wire before, nor seen the process of bending.
In the most recent study the crows demonstrated equally remarkable behaviour. They were provided with a tool that was too short to reach their food. Incredibly, instead of just giving up, they used this short tool to obtain an otherwise out-of-reach, longer tool which they used to retrieve the food. This ability to combine tools was thought to be a major advance in our own evolution, and has never before been seen in a non-primate.
The presence of such flexible and creative problem-solving in a non-human is striking enough, let alone that the species in question is a bird. Perhaps it is time to rethink the notion that primates (and by extension ourselves) are in some way 'superior'. There are also important ethical implications for our own behaviour. The New Caledonian crow was virtually unknown fifteen years ago, yet now is an important research species. Which other species have we similarly underestimated? More worryingly, which species have we unwittingly destroyed that could have shown us equally fascinating, and humbling, behaviour?
This article was written by Jo Wimpenny, PhD student at the Department of Zoology, Oxford University.
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Figure 1. New Caledonian crows rival even chimpanzees in their manufacture and use of tools (photo courtesy of Simon Walker).