Washington, August 12 : A recent study has suggested that the memories that old female elephants have of distant, life-sustaining sources of food and water, may be the key to survival for herds during tough times like climate change.
The Wildlife Conservation Society and the Zoological Society of London (ZSL) carried out the study.
According to the study, experienced elephant matriarchs seem to give their family groups an edge in the struggle for survival in periods of famine and drought.
"Understanding how elephants and other animal populations react to droughts will be a central component of wildlife management and conservation," said Wildlife Conservation Society researcher Dr. Charles Foley, lead author of the study.
"Our findings seem to support the hypothesis that older females with knowledge of distant resources become crucial to the survival of herds during periods of extreme climatic events," he added.
Specifically, the study examines patterns of calf mortality during the drought of 1993 in Tanzania's Tarangire National Park, the most severe drought in that region in the past 35 years.
During a nine-month period of that year, sixteen out of 81 elephant calves in the three groups studied died, a mortality rate of 20 percent. The normal mortality rate of calves during non-drought years is a mere two percent.
When compared with other data, researchers noted correlations in calf survivorship with the movements of the groups and, in particular, the ages of the female members within those groups.
Of the three elephant groups observed during the event, the two groups that left the park suffered lower mortality rates than the group that remained in the northern portion of the protected area.
The researchers speculated that these elephants succeeded in finding sufficient food and water outside the protected area to keep themselves and their young alive.
The group that stayed suffered 63 percent of the mortality for the year.
The researchers pointed out that the groups that left the park may have benefited from the specific experiences of their oldest matriarchs, which perhaps were able to draw upon memories of an earlier drought and how they survived it.
The case is strengthened by the known life history of the oldest matriarchs in these groups, some of which were five years or older during the drought of 1958-61.
The group that remained in Tarangire in 1993 had no individuals old enough to remember the event.
"It's enticing to think that these old females and their memories of previous periods of trauma and survival would have meant all the difference," said Foley.
"The data seem to support the speculation that the matriarchs with the necessary experience of such events were able to lead their groups to drought refugia," he added.