April 3, 2014
Crows As Smart As 7-Year-Old Humans
It has been known for a long time that birds, like many other animals, can learn skills that help them survive. Learning is one thing, but true reasoning is another thing altogether and it is often thought that only the higher orders of animals can use logic and reasoning. New research, however, has demonstrated clearly that crows can use their reasoning powers to solve problems and perform tasks. In fact, in some tests, they performed as well as seven-year-old children.
There are lots of examples of bird intelligence from the use of tools such as sticks to extract food to using bait for fishing by dropping an insect on the water surface to attract fish. In China, Cormorants are often used to catch fish and have learned to count. The fisherman ties a cord around the bird’s neck to stop it swallowing the fish, but releases the cord after seven are caught so the bird gets to eat number eight. If the fisherman fails to untie the cord after seven fish, the birds throw a big sulk and refuse to dive. But for brainy birds, you can’t beat a crow. Crows are smart, really smart. Some Japanese crows have even been seen placing nuts near the wheels of stationary vehicles waiting at red lights then picking up the broken nuts when the vehicle drives off.
There are many species of crows, or Corvids, around the world. All are recognised as among the most intelligent of birds. In humans and many other animals, the main area of the brain associated with intelligence is the cerebral cortex, but in most bird species, the cortex is relatively small. What birds have that humans don’t is an area at the front of the brain known as the hypertriatum. Neurologists have discovered that bird intelligence has its base in the hypertriatum and that this area is larger in Corvids than in other species. The ratio of brain to body size is also greater in Corvids approaching that of humans and dolphins. No wonder then that scientists testing bird reasoning chose crows for their experiments.
Researchers at the University of Auckland, New Zealand, put Caledonian Crows through a series of tests to measure their understanding of causal relationships, the essence of reasoning. Caledonian Crows have been observed making tools and hooks from sticks to pull grubs out of trees so seemed a perfect choice. In one task, the “water displacement” test, food was placed in water filled tubes. The crows had to work out how to get at the grub. It was a breeze. They soon realized that dropping heavy not light, and solid not hollow objects, into the tubes raised the level enough for them to obtain their food reward. They also chose high water-level tubes over those with lower levels and water filled tubes over those containing sand.
Although the birds flunked a couple of more elaborate reasoning tests like getting food from a U-shaped tube, their understanding of the effects of volume displacement was equal to that of the average five to seven-year-old child.
If you would like to see more detail you can read the full research findings on PLOSONE.
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