In the elephant world, the matriarch rules, dominating the often large families made up of babies, juveniles and other females.
But the most important member of all, according to a new study, is the grandmother – the oldest of the females who can have the biggest influence on whether or not a female successfully reproduces.
“It was an unexpected finding for us,” said Professor Phyllis Lee, lead researcher of the study. “We didn’t think we’d find that very positive relationship between having a grandmother present and how well the daughters were doing in terms of reproduction.”
In the animal kingdom there are very few species that are organised in such a family-oriented way. Out of the mammals, mostly humans, whales and elephants live to see their grandchildren, let alone have an active role in their lives.
According to the study, the age and health of the grandmother has more of an influence on how long the grandchild will live, than the health and age of the mother: “Calf survival goes hand-in-hand with maternal experience and environmental conditions in the calf’s first year of life, but is not directly related to the mother’s age. First-born calves, those born during a drought and male offspring are more likely to die earlier than others. Even the oldest mothers (aged over 50) raised offspring successfully, although, like the mothers of sons, older mothers have slightly longer intervals between births.”
“The new and exciting part of our study is the strong effect females have on the reproduction of daughters and granddaughters in their family” says Lee. “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. Only ten of the 281 mothers monitored ceased reproduction towards the end of their lives.”
Looking at more than 800 individual elephants in Kenya’s Amboseli National Park, researchers collated over 40 years of data. But according to Lee, “we’re only halfway there, we need another 40 years of data.”
As the study progresses, Lee and her researchers hope that these current findings will pave the way for further studies into human relations, namely what we know about menopause and ageing.