When you think of an intelligent animal, most people probably picture the same critters: chimps, dolphins, or dogs. But many scientists believe that corvids – the group containing crows, ravens, rooks and jays – also deserve a position at the top table. They’ve shown through many experiments that crows display high cognitive abilities, often on par with those classically ‘intelligent’ animals.

The notion of what makes something intelligent has been re-written more times than can probably be counted. It used to be thought that we occupied a unique position amongst the animals as an intelligent, self-conscious, cognitive being that's able to craft tools, solve complex problems and reason about other people’s states of mind. Slowly but consistently, these benchmarks have been proven to be shared across other members of the animal kingdom.

Most of these examples have simply been inferred in crows, as no one can know for certain just by observing the birds' behavior how their minds are working. But some researchers are trying to change this, with John Marzluff and others at the University of Washington planning to scan the birds’ brains as they perform tasks to see which areas are active.

Many animals have passed the mirror self-recognition test, which requires the animal in question to realize that who it sees in the reflection is actually itself. But that is only one of many different signs of intelligence. Crows and their corvid kind have repeatedly been shown to cover far more of the intelligence bases than had ever been thought possible a decade ago.

^{Crows demonstrating that they understand water displacement. Credit: PLoS Media}

When a crow has too much food to eat in one sitting, for example, it does what many other animals will do with a surplus and hide anything extra for later. But if the bird knows it’s being watched – by either another crow or even a human – it will go back later to its stash and move it in order to stop any potential thief from pinching it.

Some have suggested that this might be a simple cause-and-effect, meaning the bird has learned that if it’s seen storing the extra food, the chances are that it won’t be there when the bird returns later to eat it. But others say that this behavior, observed again and again in both wild and captive populations, proves the crows possess what’s called “theory of mind,” being able to see a situation from another being's point of view. Essentially, they know that you know where the food is hidden.

Another ability crows excel at is toolmaking. Through many different experiments, they’ve been shown to be able to use exactly the right tool needed for a job the first time around, even when they’ve never experienced the problem before. New Caledonian crows go one step further and, rather than simply using tools, actually craft them, putting them in the exclusive group of only chimps, orangutans and humans known to manage this in the wild.  

Many suspect that corvids and mammals, while outwardly appearing vastly different, have simply come upon a similar solution – that of higher cognitive thinking – to a shared environmental pressure. This would make such high levels of intelligence yet another example of convergent evolution, where distantly related organisms independently evolve similar traits.     

[H/T The Washington Post]