Summer 2006

Table of Contents

Little brownbat (Myotis lucifugus)

We could learn about aging from bats

Bats have long been known to be a major exception from the general pattern for mammals of larger species being longer-lived, with many living past 20 years.

But last year a new longevity record for a bat species was set that has scientists urging more study of bats to learn about aging in general.

A wild male Brandt’s bat (Myotis brandtii) was recently recaptured in the Birhusa karst region of Siberia in Russia 41 years after it was originally banded there, eclipsing the old record of 34 years and making it the world’s longevity champion among small mammals.

The discovery was made by researchers from the University of Texas Health Science Center’s Barshop Institute for Longevity and Aging Study in San Antonio, and the State Nature Reserve “Stolby” in Krasnoyarsk, Russia, who wrote in a Journal of Gerontology article:

“In terms of its longevity quotient, which is longevity standardized by body size, M. brandtii lives 9.8 times longer than expected – the highest value reported for any mammal, even those maintained in captivity. The fact that this animal could survive this long in the wild indicates very well-preserved function. That is, the animal had to have well-maintained high frequency hearing to detect prey with its echolocation, as well as fly fast enough, and maneuver with enough agility, to capture prey and avoid predators on a daily basis.”

Long hibernation by bats in general is thought to be a cause of such exceptional longevity, and Brandt’s bats in Siberia do hibernate from late September through mid-June. Choosing hibernation sites within caves that are highly buffered from the outside environment also seems to be a factor.

Long-lived bats also seem exceptionally placid, not struggling hard when being captured and handled, and returning to hibernation very quickly. This could mean they are particularly deer or long hibernators.

All documented long-lived individual bats are males. Males spend longer in hibernation than females, which have to awaken earlier to join maternity colonies. Pregnant females are likely to be less agile in flight and may be more susceptible to predation. Females also have high energy demands during lactation as they suckle young.

The little brown bat (Myotis lucifugus), which occurs here in Washington, is another exceptionally long-lived species, documented to live up to 34 years in the wild. Studies of little browns indicate they are particularly resistant to oxidative damage to organs and tissue over time, and they might have “stress-resistant” DNA.

The Brandt’s bat researchers call all of these findings “provocative.”

“Little is known of basic biology of bat cells. Our results at least suggest that bats might have exceptional defense mechanisms against cellular damage…..We hope that this report will stimulate interest among biogerontologists to consider bats seriously as study organisms in a comparative approach to aging research.”

Meanwhile, our layman’s interpretation suggests that laid-back males who sleep a lot might outlive us all!