Wet Nurses of Golden Snub-nosed Monkeys

Text by Zhai Xingbo,Zhang Shanshan & Liu Junshan Photos by Jiang Yong

In Dalongtan Scientific Research Basein Shennongjia,a baby monkey named “Tianzhen” is feeding at a “mother’s” breast.The mother is not its biological mother but one of the two wet nurses.These mother monkeys will help “Tianzhen” get through the frigid winter and early spring.The team,led by Researcher Xiang Zuofu and Li Ming has spent five years in Shennongjia and discovered the “wet nurse phenomenon” among golden snub-nosed monkeys.A paper on this discovery was published in Feburary of this year inScience Advances,a journal of theSciencefamily.

In 2006,the team began to research golden snub-nosed monkeys.However,it is difficult to distinguish baby monkeys since they are similar in color and figure.In the spring of 2011,they were surprised to find a female monkey feeding two baby monkeys at the same time.Allomaternal nursing was also found among other golden snubnosed monkeys—especially in the winter.This kind of monkey is mainly found in Hubei,Sichuan,Shaanxi,and Gansu—places with high altitudes and long winters that span from October to April.Females who give birth to babies usually fail to provide enough milk because of a lack of food in the cold weather.

The team had also found that the “wet nurse phenomenon,” as a collaborative way to cope with problems,is emblematic of the great wisdom of golden snub-nosed monkeys to keep more newborns alive.Follow-up surveys over the next five years indicated that 40 out of 46 baby monkeys here were fed by one or several wet nurses,accounting for 87%; 22 were fed by two or more wet nurses,accounting for 48%; four out of the remaining six monkeys,which were not fed by wet nurses,died in the cold winter.By comparison,only six of the 40,fed by at least one wet nurse,died.The mortality rate decreased markedly.“Without wet nurses,the golden snubnosed monkeys could have become extinct.” said Xiang Zuofu.

Research has also found that allomaternal nursing behavior only appears in the first 3 months or less after the baby monkey is born.It stops when the baby monkey is able to eat food other than milk.At that time,the baby can probably survive the winter,for they begin to grow faster and can better resist the cold.Through repeated observation and video tracking,experts concluded that allomaternal nursing appears between females with kinship ties,like the granny or aunt of the baby monkey.“Around 90% of female monkeys nurse other monkeys’ babies whose mothers had fed their own babies within that year or the next as a return.”

Xiang Zuofu said,the female monkeys allow other females to touch their offspring at an early age,which is essential for the emergence of the babymother-wet nurse relation,quite similar to early stages of human evolution.Hence,the research sheds a new light on the understanding of human evolution.

(Translation: Tang Lin)

Located at the same latitude as the Bermuda Triangle and the Pyramids, Shennongjia is full of mysterious phenomena,and called “the gene pool of global species.” Many old and spectacular species,phenomena,behaviors,topography, and landforms are protected here. The golden snub-nosed monkey is one of most endangered monkeys in the world and a first-class national protected animal.