World's smallest primates live longer than previously thought

The world's smallest primates, the mouse lemurs, can live at least eight years in the wild - twice as long as some previous estimates suggested, a recent study revealed.

Mouse lemurs are found only on the island of Madagascar.

The study determined ages of wild mouse lemurs in Madagascar's Ranomafana National Park through a dental mould method that had not previously been used with small mammals.

"We found that wild brown mouse lemurs can live at least eight years," said Sarah Zohdy, biologist at the Emory University in the US.

For the study, wild brown mouse lemurs were trapped, marked and released between the years 2003 to 2010.

A total of 420 dental impressions were taken from the lower right mandibular tooth rows of 189 unique individuals.

Over the course of seven years, 270 age estimates were calculated.

Starvation, predation, disease and other environmental factors may reduce the observed rate of senescence (biological ageing) in the wild, Zohdy noted.

"More interestingly, we found no difference in testosterone levels between males and females," added Zohdy.

The fact that wild mouse lemurs hibernate for half the year, possibly boosts their life span, Zohdy said.

"Comparing longevity data of captive and wild mouse lemurs may help us understand how the physiological and behavioural demands of different environments affect the ageing process in other primates, including humans," concluded Zohdy.

The study appeared in the journal Plos One.