Maleficent was right to have ravens by her side, after all. The creature has been shown to be as intelligent as chimpanzees in spite of their smaller brains. Again, we find that size is not necessarily a restriction. The study is published in Royal Society Open Science.
Researchers from Lund University, Sweden, have found that the neuronal density as well as the structure of the brains of ravens account for an intelligence that is comparable to that of chimps. Ravens might thus not have big brains, but this does not mean they are any less clever.
The performance of these corvid birds is similar to the great apes, says study author Can Kabadayi. This conclusion was reached after the team analysed data concerning the inhibitory control — the ability to get past animal instinct to choose what is more rational — of 36 species of animals (mainly apes and the likes). Inhibitory control is a trait used to test intelligence. The animals were exposed to food placed in a transparent container bearing openings on two sides; the trick was for them to obtain the food through the side openings instead of reaching out for it directly which would be encouraged by their animal instinct. This might seem like an easy thing for humans, but for animals, it demands self-restraint so that they can implement a more efficient technique to retrieve the food.
The results show that great apes had the best performance. Does this imply that absolute brain size determines intelligence level? Absolutely not. This is so because when ravens, and their relatives like jackdaws and New Caledonian crows were made to go through the same test, they, too, were able to make the better choice: all of the ravens opted for entering the tube from the sides, while most of the jackdaws and crows performed as well; the latter’s performance matched that of bonobos and gorillas.
The authors, thus, explain that smaller absolute brain sizes can be efficient. Rather, neuronal density might be a factor playing a role in intelligence. Kabadayi exclaims that “bird brains are not simply birdbrains after all!”