Photo: Rugani et al.
They may be just 3 or 4 days old, but chicks can already do simple arithmetic. Inspired by experiments with human babies, Rosa Rugani of the University of Trento Center for Mind/Brain Science in Italy and colleagues decided to test chick's mathematic abilities:
... Rugani and her colleagues worked out tests based on adding objects to and taking them away from little piles behind screens. With no special math coaching, the chicks did a decent job of keeping track of object shifts representing such problems as 4 – 2 = 2 and 1 + 2 = 3, she and her colleagues report online March 31 in Proceedings of the Royal Society B.
“This is the first demonstration of adding and subtracting in young animals” other than humans, Rugani says. Other animals, including some primates and dogs, have demonstrated numerical powers as adults.
If you took some of the eggs they had in the nests, they would lay exactly that same number back again.
It was obvious they were counting.