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Sci Tech
Corvis Sapiens — bend it like Betty!
I WANT to let you in on a free 40- second video that you must watch on the incredible feat of the common crow. Go now to a computer, access .org on the internet, and you will get to the journal Science.
Go to the archives lines and ask for the August 9, 2002 issue. Click there on the "Table of Contents", go to the section called "Brevia" and get the article by Weir, Chappell and Kacelnik. You cannot access the full text unless you have a subscription and a password.
But you can click at the material called "supplementary material". This has a video movie, which you can watch by downloading it using "Quicktime". You do not have to pay for this, it is free! And to add to your pleasure, watch a crow bend a straight wire into a hook. It then uses the hook to lift a small bucket of food from a glass cylinder! The experiment was done by the three Oxford zoologists named above, who also put this movie out free for you to marvel at.
The Oxford experiment went like this. They had read about earlier reports by the New Zealand psychologist Dr. G. R. Hunt on the ability of the crows from the Pacific island New Caledonia to design tools for specific purposes. He found them to make hooks from pandamus leaves, and also to bend the hook in a right handed or left handed to suit the need. (He also wondered whether, like humans, birds and animals too may have preferred "handedness"). They extended this idea and decided to challenge the crow into making tools for a specific purpose. A female New Caledonian crow (called Betty) and a male (Abel) were brought before a glass cylinder in which a tiny bucket containing a small piece of meat was kept.
The birds also were given a choice of a straight wire and one bent as a hook at the end. Abel, the bigger of the two, immediately grabbed the hook and lifted the bucket and took off with the meat (and the hooked wire). Now Betty was asked to lift the bucket with meat in it. All she had was a straight wire. She had no previous experience of bending wires to fall back on, though she was allowed to play with other pliant material like a tobacco smoking pipe cleaner. She had to "think on her feet", as it were.
Bend it like Betty!
What Betty did next was stunning. As the video shows, she tried the straight wire with no success. Then she took the wire on her beak, tapped it on the ground a few times, and Eureka!, bent it into a hook and lifted the bucket. Was this a fluke, or an act of thinking? To be sure, the scientists asked her to try again, 10 times, each time with a straight wire. She came out in flying colours (I realise how mixed the metaphor is, for a black crow, but some licence must be granted given the incredible act), scoring 9 times out of ten. The authors remark, deadpan in the notes following their report, that Abel "the male rarely attempted this task and never bent the wire. He observed Betty bending the wire and stole the food from her in three trials. The birds are tested together because they are highly social and, when separated, are less motivated to participate in the experiments". Male chauvinism and gender exploitation is not the province of humans alone.
The experiment shows that at least one of the two birds is capable of making a novel tool suited for the task on hand. Betty had no previous experience, no model to imitate, and no opportunity for tool-making. Apparently she thought about the problem and devised a solution.
Now, that is called intelligence— solving a problem by thinking about it and devising an answer. Thinking and problem solving are not the exclusive domain of primates such as apes and us. The New Caledonian crow may as well be renamed Corvus moneduloides sapiens.
The Nutcracker Suite
There are earlier instances of the smartness of the common crow. My colleagues at Trieste, the town on the Adriatic coast of Northeast Italy, have seen crows pluck walnuts from trees and drop them from a height on the concrete ground.
The nut cracks and the crow swoops off the booty. And when the tide is low, they pick up clams from the shore and drop them like walnuts, to eat off the meat. Crows in Japan have gone "street smart", or "traffic light smart". They perch on the bonnet of halting cars at the stop light and drop walnuts on the road ahead of the car.
When the light turns green, the car tyres crack the shell, and the bird returns when the light turns red next to carry off the meat from the broken nut!
Apparently, crows have the concept of numbers and can count up to seven. A very clever experiment was devised to determine this. A number of small cups are placed on the ground, each with some pieces of meat- 0, 1, 2,3... varying numbers, each with a lid on. The crows are trained to lift the lid and eat as many from each cup as they want. Next to these cups is an open plate with meat, the total pieces there being more than the sum of all those in the cups. The crow has to eat the same number from the plate as it did from all the cups put together. If it eats more, it is punished. The bird learns, but up to seven and no more!
Birds and bees, and brains
Crows are not the only birds with intelligence. All in the corvid family- ravens, jackdaws, magpies and rooks are smart too. Eagles are known to do the "walnut act", with live tortoises that they carry off. Woodpeckers, finches and parrots are reported to think and act. Ravens are known to gather together, and supply and share information about carrion and carcasses. Such behaviour, it has been remarked, comes not just due to physical need, but also as a social necessity. The complexities of living together requires a higher level of thinking and intelligence.
At its most fundamental level are the ants, termites, bees and wasps. As Lewis Thomas has remarked: "One ant is just a bunch of neurons on legs. Put a few ants together — an idea is born".
Is this how a brain is born — an integration of neural circuits in tandem or in parallel so as to produce a higher order computing system? Indeed, there is the question of brain size, or more appropriately, the ratio of brain size to body size. In humans, the brain weighs less than 2 kg, making the brain/body ratio about 1: 40. The mouse weighing about 20 g, has a brain of about 0.4 g, giving the same ratio of 1: 40, making it potentially as smart as man. A bird of, say 85 g, has a brain size anywhere between 0.8 g (quail) and 2.7 g (woodpecker). The ratio in birds is thus only slightly smaller than in mammals. Dr. Thomas Jully, a veterinarian from the Louisiana State University, says that a parrot can easily be toilet trained, and obeys the "potty" command well. Its linguistic ability is only too well known. When a parrot pecked Jully's cheek, he said "Oh, it hurts". Next time, when a toy fell on its feet, the parrot cried out: Oh, it hurts.
The Panchatantra tales, which tell us about the smartness of birds and animals, place the fox as smarter than the crow. A fox wanted the piece of meat that the crow, perched on a tree, was carrying in its beak. The fox goes on a praising spree, telling the crow how beautifully she sings. The crow readily shows off with her caw, dropping the meat for the fox to carry off. I shall now wait to see if a fox can bend a wire into a hook to snag the meat off the Oxford bucket.
D. Balasubramanian
dbala@lvpeye.stph.net
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