An international team of researchers including The University of Western Australia and China's Central South University of Forestry and Technology has discovered that female golden snub-nosed monkeys in China are happy to feed other monkeys' offspring.
The research, published today in Science Advances, revealed that almost 90 per cent of infant golden snub-nosed monkeys were nursed by females other than their mother.
An endangered species found in the seasonally cold mountainous forests of south-west China, the golden snub-nosed is an Old World monkey lives in complex social groups.
Co-author Dr. Cyril Grueter, senior lecturer in UWA's School of Human Sciences, said although humans had been known to practise wet nursing over many centuries, little was known about the practice in our primate relatives.
"What we found was that the milk sharing was confined to the first three months of the infant monkey's life and it occurred predominantly between related females who shared nursing duties in a reciprocal manner," Dr. Grueter said.
"Infants that received additional doses of milk from females other than their mother had a higher chance of surviving.
"We believe that this behaviour may provide a buffer for mothers and young against the vagaries of their harsh environment."
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Zuofu Xiang et al. Routine allomaternal nursing in a free-ranging Old World monkey, Science Advances (2019). DOI: 10.1126/sciadv.aav0499