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 member of the group.
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, Professor Andrew Whiten (both St Andrews) and Professor Redouan Bshary (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.
Dr van de Waal, a research fellow of the Swiss National Science Foundation, based at the School of Psychology and Neuroscience at St Andrews said: "A lot of recent research has led to the view that monkeys and apes are not so very faithful in what they learn by observing others, but our results suggest that in some contexts the copying can be quite detailed and the mother-infant relationship may be particularly influential in primates like these".
Professor Whiten, Professor of Evolutionary and Developmental Psychology at St Andrews, added: "Some studies have shown that we humans acquire most of our cultural knowledge directly from our parents. Our new results add to increasing evidence that the same may be true for many birds and mammals and reflect an ancient evolutionary heritage".
The findings are published in the latest issue of the scientific journal, Animal Behaviour.