Thinking for themselves

language,' said Pepperberg. 'My plan always was to use his imitative skills to get a better understanding of avian cognition.' Given that Alex's brain was the size of a walnut, most researchers thought Pepperberg's study would be futile. But by the time Alex died in 2007, he knew 150 words, could count, do simple arithmetic, and distinguish between objects according to shape, color, and material. Many of Alex's skills, such as his ability to understand the concepts of 'same' and 'different', are generally ascribed only to higher mammals. But parrots, like higher apes (and humans), live in complex societies, and need to monitor changing relationships and environments. 'They need to distinguish colors to know when a fruit is ripe or unripe,' Pepperberg noted. They need to categorize things - what's edible, what isn't - and to know the shapes of predators. And it helps to have a concept of numbers if you need to keep track of your flock. For a long-lived bird, you can't do all of this with instinct; cognition must be involved.'