Teen Elephant Moms Die Earlier, Have More Offspring
Teen mothers die earlier but have bigger families, according to new research on elephants.
Scientists found that Asian elephants that give birth as teens die younger than older mothers. However, teen mothers raise bigger families during their lifetime.
The latest study involved 416 Asian elephant mothers in Myanmar, Burma. Scientists at the University's Department of Animal and Plant Sciences found elephants who had calves before the age of 19 were almost two times more likely to die before the ages of 50 compared to elephants that had gave birth later.
However, elephants that gave birth before the age of 19 had more calves than those that gave birth after the age of 19.
Researchers said the latest findings could help improve fertility in captive and semi-captive elephants, reducing the strain on the endangered wild population.
The study also revealed that elephants that gave birth twice in their teen years had offspring three times more likely to survive to independence compared to those who had their first young after the age of 19.
Researchers said the latest findings suggest that natural selection favors early reproduction because young elephant mothers raised the largest families in their lifetime.
"Understanding how maternal performance changes with age and impacts on later-life survival and fertility is important. Asian elephants are endangered in the wild and low fertility in captivity necessitates acquisition of elephants from the wild every year to maintain captive populations," lead researcher Dr. Adam Hayward, of the University of Sheffield's Department of Animal and Plant Sciences, said in a news release
"Our research was carried out on semi-captive Asian elephants working in timber camps in Myanmar," Hayward said. "As religious icons in South-east Asia and a key species of the forest ecosystem, their decline is of serious cultural and ecological concern."
"Our results will enable the management of captive and semi-captive elephants to be tailored to maximize fertility, reducing strain on the wild population," he added.
"We rarely get the opportunity to study how other species with a lifespan similar to humans grow old," added Virpi Lummaa, Reader of Evolutionary Biology at the University of Sheffield.
"This study represents a unique analysis of the ageing process in a similarly long-lived mammal," Lummaa said. "It also supports the evolutionary theory that selection for high fertility in early life is energetically demanding, which accelerates declines in survival rates with age which are typical of most animals."