Scientists find routine allomaternal nursing in an Old World monkey

A team of scientists led by Prof. LI Ming of the Institute of Zoology, Chinese Academy of Sciences, found widespread allomaternal nursing behavior in nursing others' offspring in an Old World monkey, the golden snub-nosed monkey.

The findings were published in an article entitled "Routine allomaternal nursing in a free-ranging Old World monkey" in Science Advances on Feb. 20.

The evolution of lactation in metatherian and eutherian mammals has resulted in a large degree of nutritional and developmental dependency between a female and her offspring.

Milk production is energetically costly for mothers since they need to synthesize and provide nutrients, hormones, vitamins, and immune compounds. Therefore, lactating females should be reluctant to invest time or energy in nursing others' offspring.

While regular allomaternal nursing has been documented in a number of rodent and carnivore species, as well as in some prosimians, New World monkeys and humans, it is not common in Old World monkeys and apes.

Based on more than eight years of field observation of infants and their mothers at Shennongjia National Park, Central China, as well as analysis of the monkeys' reproductive histories, the study provides the first evidence of regular allomaternal nursing in golden snub-nosed monkeys (Fig. 1) and expands the taxonomic distribution of this behavior in primates to Old World monkeys.