“This study shows that the unique bill contributes to the birds’ ability to use and probably make tools,” he said. “We argue that the beak became specialized for tool manipulation once the birds began using tools, and that this enhanced tool manipulation ability may have allowed the crows to make more complex tools.”
Probably. It works that way with appendages too.
In fact, some differences in apparent animal intelligence may come down to whether the animal can carry out an action for its own benefit. Shellfish are closer anatomically to octopuses than birds are but both octopuses and birds can use body parts to do something. Shellfish can’t. Can we quantify intelligence apart from the ability to demonstrate it?
Birds with blunter, straighter bills were probably more adept at handling tools for foraging and over time those features evolved, McGowan said. Tool use has now become ingrained in the crow’s biology. In the case of the New Caledonian crow’s beak, you might say it’s not so much “you are what you eat,” but “you are how you eat.”
Did the bills “evolve” or merely adapt? Let Darwin’s finches be a cautionary tale. (Their beaks simply adapted, probably via hybridization, to changing conditions; it was not the big Evolution Story trumpeted a few years ago.) We’ll see.
The question that cannot be answered is why the crows started using tools in the first place. It may have been a matter of chance because most birds do just fine foraging with their beaks and feet without resorting to tool-making, McGowan said. More.
Vincent Torley, where are you? (One of our resident philosopher authors, Torley did his thesis on animal minds.)
Presumably, to use tools, the animal must not only seek to continue living (a characteristic of all life forms) but envision extending its appendages’ skills by co-opting an object (non-self), to pursue that goal. How does it gain this ability? Probably not “by chance,” as suggested. There is more to the story. And that’s the next big question.
See also: What can we hope to learn about animal minds?
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Here’s the abstract:
(public access) Early increased sophistication of human tools is thought to be underpinned by adaptive morphology for efficient tool manipulation. Such adaptive specialisation is unknown in nonhuman primates but may have evolved in the New Caledonian crow, which has sophisticated tool manufacture. The straightness of its bill, for example, may be adaptive for enhanced visually-directed use of tools. Here, we examine in detail the shape and internal structure of the New Caledonian crow’s bill using Principal Components Analysis and Computed Tomography within a comparative framework. We found that the bill has a combination of interrelated shape and structural features unique within Corvus, and possibly birds generally. The upper mandible is relatively deep and short with a straight cutting edge, and the lower mandible is strengthened and upturned. These novel combined attributes would be functional for (i) counteracting the unique loading patterns acting on the bill when manipulating tools, (ii) a strong precision grip to hold tools securely, and (iii) enhanced visually-guided tool use. Our findings indicate that the New Caledonian crow’s innovative bill has been adapted for tool manipulation to at least some degree. Early increased sophistication of tools may require the co-evolution of morphology that provides improved manipulatory skills. – Hiroshi Matsui, Gavin R. Hunt, Katja Oberhofer, Naomichi Ogihara, Kevin J. McGowan, Kumar Mithraratne, Takeshi Yamasaki, Russell D. Gray, Ei-Ichi Izawa. Adaptive bill morphology for enhanced tool manipulation in New Caledonian crows. Scientific Reports, 2016; 6: 22776 DOI: 10.1038/srep22776