Grandmas play a very important role in the long-term success of an elephant herd, reveals University of Stirling research.
Phyllis Lee, Behavioural Psychologist at the University of Stirling, led a study analysing data from 834 female elephants in Amboseli National Park, Kenya. Researchers have been watching more than 3000 elephants in Amboseli for more than four decades.
Phyllis Lee, Behavioural Psychologist at the University of Stirling, said:
"We didn't think our study would find a very positive relationship between having a grandmother present and how well the daughters were doing in terms of their reproduction. However, our research found that old mothers have a strong effect on the reproduction of the daughters and granddaughters in their family.
"Having an experienced mother, one who knows how to respond to their calf's demands and how to keep them close by, makes a huge difference in whether a baby elephant survives- having a grandma adds much needed extra help. Females support each other and protect and care for calves as a group."
Prof Lee added: "Daughters of long-lived mothers lived longer themselves and had higher reproductive rates. In some large families, three generations of mother-daughter pairs reproduced simultaneously."
The study found only ten of the 281 oldest mothers ceased reproduction towards the end of their lives followed by up to sixteen years of post-reproductive survival. The selective disappearance of less productive individuals has not been seen for such a long-lived animal before.
Lee added: "While elephant calves clearly get a major survival and reproductive benefit from having a living grandmother, the females do not exhibit classical forms of menopause or cessation of reproduction long before death, as seen in whales and humans."
The full study is published in the Behavioral Ecology and Sociobiology.