A new Duke University study of long-living lemurs holds the promise of eventually pointing the way for researchers to identify human genes that could help us live longer, healthier lives.
“It’s one small piece of a very large puzzle,” said study co-author Sarah Zehr, a research scientist at the Duke Lemur Center.
The study of small primates – three species of lemur plus a species of bushbaby – found a correlation between hibernation and both longevity and staving off age-related diseases.
“Some of the aging processes seem to be able to be slowed down when an animal is in hibernation,” Zehr said. “You put your aging on hold while you’re hibernating. ... So, cumulatively, over your life, you degenerates less. That’s the theory anyway.”
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The link between hibernation and longevity previously was established by scientists who studied animals such as rodents and bats. But the study by Zehr and co-author Marina Blanco, a fellow scientist at the Lemur Center who is currently doing field work in Madagascar, is notable because it involved primates.
“Humans are much more closely related, evolutionarily speaking, to the lemurs,” Zehr said.
Consequently, if scientists identify the lemur genes that correlate with hibernation and a longer life span, they are much more likely to find “matching correlations in human genes,” Zehr said.
In addition, the study was able to exploit the Lemur Center’s extensive database to show that fat-tailed dwarf lemurs, which hibernate the most of the four species studied, “also live a larger proportion of their lives without disease” associated with aging, Zehr said.
The study recently was published online and is scheduled to appear in an upcoming issue of the peer-reviewed Journal of Zoology. As with all studies conducted at the Lemur Center, no invasive procedures were conducted.
“We don’t allow harmful research at the Lemur Center,” Zehr said.
The study looked at 971 lemurs and bushbabies in the Lemur Center’s database, which goes back nearly 50 years.
“We know when they were born. We know when they died. We know when they got sick. We know when they reproduced,” Zehr said.
Although scientists have shown a correlation between body size and longevity – “Mice don’t live very long, elephants live a long time,” Zehr said – the lemurs included in the study are an exception to this pattern.
Although the lemurs range in size between that of hamsters and squirrels, their median life spans ranged from 8.47 years to 15.1 years for the fat-tailed dwarf lemur. The longest-living dwarf lemur known, Jonas, was five months shy of his 30th birthday when he died at the Lemur Center in January.
Not coincidentally, the dwarf lemurs also hibernate the most among the animals studied – three to seven months in the wild. In captivity, rather than entering months of hibernation, the dwarf lemurs mostly go into an abbreviated, semi-hibernation state called torpor. They do this on a daily basis for as long as three months.
But even torpor appears “to confer extended longevity,” Zehr said.
The study also compared the dwarf lemur’s longevity with other animals and found that it lives two to three times longer than similar-sized animals.