Both sets of newcomers seemed to follow social cues when selecting their snacks. Baby monkeys ate the same colour maize as their mothers. Seven of the ten males that migrated from one colour culture to another adopted the local colour preference the first time that they ate any maize. The trend was even stronger when they first fed with no higher-ranking monkey around, with nine of the ten males choosing the locally preferred variety. The only immigrant to buck this trend was a monkey who assumed the top rank in his new group as soon as he got there — and he may not have given a fig what anyone else ate.
“The take-home message is that social learning — learning from others rather than through individual trial and error — is a more potent force in shaping wild animals’ behaviour than has been recognized so far,” says Andrew Whiten, an evolutionary and developmental psychologist at St Andrews and co-author of the paper.