The significant role played by grandmas in Asian elephant groups

Mirkka Lahdenperä, Khyne U. Mar and Virpi Lummaa, researchers from University of Turku in Finland have come to the conclusion that to ensure the survival of the calves and breeding success for their daughters, the grandmothers plays a significant role in Asian elephants.

Asian elephants have a lifespan of up to 80 years and live in highly social family groups containing many generations of females and their calves.   During the last few generations, the number of Asian elephants has dropped by half and only 38,500-52,500 elephants currently remain in the wild.   The research group studied the unique records maintained for a century on Asian elephants used in timber extraction in Myanmar.

Dr. Mirkka Lahdenperä, the lead author of the study has this to say We found that calves of young elephant mothers under 20 years of age had eight times lower mortality risk if the grandmother resided in the same location compared to calves whose grandmother was not present,"

Resident grandmothers also decreased their daughters' inter-birth intervals by one year. This has the effect of having more grandcalves. Grandmothers with own recent calves were as beneficial to their daughter's calves as grandmothers who had already stopped reproducing.

Professor Virpi Lummaa adds "Grandmothers may be particularly important for the reproductive success of their inexperienced adult daughters. Older daughters, on the other hand, would have already gained enough experience in calf rearing to succeed without the help of their mother," 

Calf mortality is very high in zoos, as up to 50% of the calves die during their first years. In addition, problems with reproduction are common.

Professor Lummaa suggests "Experienced grandmothers might be in a pivotal role in increasing the survival prospects of calves as well as female birth rates in zoos. Conservationists and captive population managers could potentially boost the elephant population by simply starting to keep the grandmothers with their offspring, similarly as would be the case in the wild in elephant families," 

Details appear in the latest issue of journal Scientific Reports