Scottish scientists have found that young monkeys adopt the different eating habits preferred by their mothers.
Researchers at the University of St Andrews, in collaboration with the University of Neuchatel, found that young vervet monkeys in the wild copy the different ways their mothers prepare food before eating it.
The new study, carried out in the wild in South Africa, supports a famous study in which a group of Japanese macaque monkeys appeared to adopt the eating habits of another group member.
Heralded as the first example of a local animal 'culture' being sustained by imitation, the group adopted the habit of a young female who washed her sweet potatoes in the sea.
At the time of the 1960s study, however, there were concerns that the new behaviour took too long to adopt and that the monkeys' behaviour was possibly shaped by human intervention, because the potato-washing individuals were rewarded.
In the new study, Dr Erica van de Waal and Professor Andrew Whiten from St Andrews University and Professor Redouan Bshary from the University of Neuchatel observed a group of wild vervet monkeys who were given grapes with sand on them.
They found that mothers displayed four different approaches to eating them: a few just ate them, but most preferred to clean the grapes first, either rubbing them with their hands, rubbing them on the ground, or using their mouths to extract the clean inner part.
In their observations of the young infants in the group, the very first approach they took was the same as their mother's. Some mothers used more than one method, and infants of these mums were likewise more likely to explore different approaches after their first attempt, when they had simply repeated the method their mothers had just done.
The findings are published in the latest issue of the scientific journal, Animal Behaviour.