Female elephants benefit from having their mother around when it comes to having infants, a study has found.

Data gathered from more than 800 elephants in Kenya's Amboseli National Park suggests grandmothers play a very important role in the long-term success of the herd.

Females were found to support each other and protect and care for calves as a group.

Professor Phyllis Lee, a behavioural psychologist at Stirling University, said: "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.

"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, published in the Springer Journal, found only 10 of the 281 oldest mothers ceased reproduction towards the end of their lives followed by up to 16 years of post-reproductive survival.

The selective disappearance of less productive individuals has not been seen for such a long-lived animal before.

Prof Lee said: "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."