LIVE FAST, DIE LAST ANDREW BAIN
In complete defiance of one of nature’s most fundamental laws, a species of tiny, frenetic bat is living 10 times longer – and healthier – than it should. talks to the research team embarking on the project of a lifetime to find out how they do it – and w
IN THE TALL CHURCH TOWERS OF BRITTANY in northwest France, the fountain of youth stirs to life each night. In scenes that might be cut from a Gothic novel, colonies of small Myotis myotis (greater mouse-eared bats) awaken from their roosts, flying out in waves into the Atlantic darkness.
Awaiting them each July for the past seven years has been an international team of scientists and volunteers, who catch them, take a tiny sample of blood and a wing punch of tissue, then release them again into their extraordinary lives. Almost unfailingly, the same individual bats will be seen again in 12 months, and likely for many years to come, because these animals have naturally mastered one of the coveted mysteries of existence: living very long and remarkably healthy lives.
Of the 19 species of mammals that live longer than humans relative to their body size, 18 are bats, including M. myotis. The other is a naked mole rat.
“There’s a rule in nature: small things live fast and die young, and big things live slow and live long,” says Emma Teeling, the University College Dublin professor and zoologist who heads the Brittany study. “Bats are some of the smallest of all mammals, yet they can live way longer than expected given their body size.”
M. myotis typically weighs around 25 grams, which is about the same weight as a laboratory mouse. But while a lab mouse will live for no more than four years, these incredible bats can live up to 37 years. In Siberia, a Myotis brandtii (Brandt’s bat) weighing just seven grams was caught and banded in 1964. It was captured again, alive and well, almost 42 years later – a timeframe that would represent around 235 years in a human. Most remarkably, the bat showed no signs of ageing.
Contrast this to the tale of human life. The World Health Organisation has predicted a 350% increase in the number of people aged over 80 by 2050, and a doubling of the number of people aged over 60, but with no equivalent increase in the health of the population. There could be 300 million more octogenarians, nonagenarians and centenarians on the planet in 30 years, but they will be no healthier than the elderly of preceding generations.
“So everyone is going to live longer, but wouldn’t it be much better if those people were also healthy?” Teeling asks. “They’ve argued in the US that if you can slow down the ageing process by two years over a 50-year time period, it’s going to save $7 trillion. It’s about matching health-span to lifespan.
“I think that if we can find novel solutions to these problems, let’s do it, but we have to look outside the box, which means looking outside humans. You have to look at animals that have naturally evolved these mechanisms.”
And what better examples, she says, than those wise elders of the mammal kingdom: the long-lived Myotis bats.
BATS OVER BRITTANY
Though the remarkable longevity and health spans of bats of the Myotis genus were already well recorded, the mechanisms they’d evolved to allow them to slow down the ageing process weren’t well understood. These bats didn’t age, and they didn’t get cancer, but how did they achieve these superpowers of health?
Teeling saw an opportunity to try to understand and explain this mystery when a French postdoctoral
and tissue taken from hundreds of bats, the first longitudinal study of its kind has yielded fascinating results.