Grandmas play an essential role in the long-term success of elephant herds.
Raising a baby elephant can be exhausting. Elephant calves are heavily dependent on their mothers for food for their first two years of life, nursing frequently throughout the day. Mothers must keep a watchful eye on their calves at all times to make sure they don’t separate from the herd.
Fortunately, help is often readily available in the form of allomothering — when other females from the herd partake in caring for calves by providing them with comfort, assistance, and protection.
According to a new study published in the journal Scientific Reports, grandmothers make vital contributions to the care of Asian elephant calves. Long-term records on elephants used in timber extraction in Myanmar revealed that calves were more likely to survive when their grandmothers were around.
“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,” said study lead author Mirkka Lahdenperä in a press release.
Resident grandmothers also reduced the number of years their daughters waited after having a baby to have another one. This meant that overall, more grandcalves were being born while their grandmothers were still alive.
“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,” explained co-author Virpi Lummaa.
Experience was also crucial for grandmothers. Those who had raised more offspring before becoming grandmothers were found to be better at reducing grandcalf mortality.
“Our results showing the essential role of the elephant grandmothers are significant for the conservation of this endangered species,” Lahdenperä said.
“In zoos, the typical multi-generational groups are rare and animals are often moved between zoos,” she continued. Up to 50 percent of the elephant calves housed in zoos die during their first years.
Meanwhile in the wild, elephant poachers often target old, large females. These results underscore the severe damage that the removal of grandmothers from the herd could cause for the younger generation of this endangered species.