With long lives and no physical signs of aging, would these bats even be interested in a fountain of youth? 

06.26.24

By Karin Akre

Fountain of Youth

Have you ever dreamed of a magical fountain of youth that could preserve your healthy glow for eternity? If we weren’t so immersed in bat biology, we might wonder if bats have actually discovered a fountain of youth where they go to drink and bathe each night, because bats can live way beyond nature’s expectations.

Brandt's Myotis
Brandt’s myotis- the longest lived bat species. Jeroen van der Kooij.

Lifetime Achievement Award

The hero of bat longevity is a male Brandt’s myotis (Myotis brandtii) from Siberia who lived at least 41 years, recognized by the band number on his forearm each time he was caught and released over the years. Forty-one years may not sound especially old given that humans are known to reach 122 years old. However, since bats are much smaller, living this long defies a standard rule of biology. This rule states that among placental mammals, longevity is tied to size. Comparing size (as body mass) with the maximum known lifespan (as longevity record in years) for each species reveals a trend (see graph). Small mammals live shorter lives (house mice: 4 years), while large mammals live longer lives (African elephants: 65 years). But when bats are added to a graph showing this relationship, all the dots representing bat species rise above the trendline. Their long lifespans lift them above the other mammals of their size, as if they are flying away in rebellion.

Many non-bat mammals live longer or shorter than expected, but bats are the taxonomic group that most consistently outlives expectations for the longest time. Scientists measure this with a handy calculation called the longevity quotient (LQ). If LQ = 1, a species’ actual lifespan matches what is expected based on size. People have a high LQ (about 4.18, depending on what species set the expected trendline), indicating we live far longer than expected for our size. The Norway rat has a low LQ (about 0.28) because it lives less than expected. Myotis brandtii consistently has the highest species LQ, coming in at 4.95, 7.834, or 9.8, depending on the study. Chiroptera, the order made up of bats, has the highest average LQ of any group of placental mammals.

A Torpor Twinkle

Why are bats so long-lived? Do they just love breaking rules? Comparing bat species provides some clues, because bat lifespan varies a lot. Many fruit bats have low LQs relative to other bats. Fruit bats can live a long time—some can live over 15 years, and a few can live 30 years. But fruit bats are the largest bats, so a longer lifespan is expected. What is surprising is how many smaller species live long lives, such as those in the genus Myotis (like our hero!). Little brown myotis (Myotis lucifugus) can live 34 years, and lesser mouse-eared myotis (Myotis blythii) can live 33 years. But curiously, not all Myotis species live extra-long lives. Black myotis (Myotis nigricans) only live 7 years. Fish-eating myotis (Myotis vivesi) can live 10 years. And outside of Myotis, the mid-sized Pallas’s mastiff bat (Molossus molossus) only lives to be 5.6 years, while the small common pipistrelle (Pipistrellus pipistrellus) lives to be almost 17 years! What gives???

A Pallas's mastiff bat is perched on wood/lumber.
Pallas’s mastiff bat. J. Scott Altenbach.
Common Pipistrelle (Pipistrellus pipistrellus) flying to hole in tree, England
Common pipistrelle. Stephen Dalton/Minden Pictures.
Myotis nigricans 2
Myotis nigricans. J. Scott Altenbach.

Many behaviors have been suggested to influence how long bats can live, including cave roosting (which may offer protection) and how many pups a female has each year (more is energy draining). A key factor in bat lifespan that is firmly established is hibernation. Comparing bats that do and do not hibernate shows that hibernating bats have a higher LQ. Fruit bats do not hibernate. Our hero, from the species M. brandtii, was in hibernation for over 8 months each year! And interestingly, this species’ lifespan varies depending on where it lives. Our hero lived in Siberia, but in other regions, M. brandtii has a lower maximum observed lifespan andhibernates for a shorter period each year. Also, bats that don’t hibernate but have regular short bouts of torpor, such as common vampire bats (Desmodus rotundus), can also have high LQ. Desmodus rotundus can live almost 30 years (LQ = about 4.3).

A large cluster of cave myotis hibernates in this north Texas cave.
Cluster of bats. Jim Kennedy.

How does hibernation impact aging? The link is still being explored, but during hibernation metabolism slows, calorie intake is paused, and less cellular waste is produced. Hibernation reduces how much energy a bat burns by being alive.

Forever Young

Does this mean we can all simply choose to sleep in late and then enjoy an off-the-charts LQ? Sadly, no. Hibernation is not the same as sleep. Also, long-lived bats have evolved genetic changes that give them the ability to stay healthy over so many years. Comparing DNA between bats with high and low LQ highlights genes that contribute to longevity. These genes control cellular activities like DNA repair,  cleaning out cell waste, and tumor suppression. For example, M. brandtii has multiple copies of a tumor-suppressor gene, so these bats may make extra amounts of that gene’s tumor-suppressing product. Comparing all long-lived and short-lived mammals identifies even more types of genes that support longevity in mammals. These genes contribute to processes such as immunity, growth regulation, and cancer resistance. Bats’ ability to live a long time is supported by an incredible network of genetic tools that orchestrate a long, healthy life.

Wrinkle-faced Bat
wrinkle-faced bat. Bruce D. Taubert.

Another amazing feature of bat DNA is that it can often avoid the changes that lead to physical signs of aging. Although many bats have gray-colored fur or fascinating face wrinkles, in bats these are fixed traits present from a young age. Research on gray hair and wrinkles as signs of human aging indicates that some of the blame for these changes lies at the very tips of our DNA strands. These tips, called telomeres, get shorter each time a DNA strand is copied for cell division. Over a lifetime, the tips can degrade so much that they disappear, unless the cell repairs them. If these tips are lost, cells become dysfunctional, and aging becomes apparent. Research on a few Myotis species shows that their telomeres do not shorten over their lives! This does not appear to be the case for all bats, but some have evolved a way to maintain long telomeres. Interestingly, some of the molecules that help maintain telomeres are more active during hibernation, and hibernating species generally have longer telomeres. With long lives and no physical signs of aging, would these bats even be interested in a fountain of youth? 

Bats at Water Tank AZ
Bat at water tank. Bruce D. Taubert.

Hydration Is Key

Just because bats have the capacity to live a long life doesn’t mean they will. How many 122-year-old people do you know? Bats face serious threats, and many species are imperiled despite their superstar lifespan potential. Access to a fountain of youth could be life saving for bats, but not because of its magic—bats just need fresh water. The State of the Bats report reveals drought to be one of the top threats to bats in North America. Insectivorous bats need water for hydration and to support abundant insect populations that can feed them. Bats’ search for fresh water and sufficient food gets longer and more exhausting as drought lingers and spreads, and extended periods of drought can kill bats. BCI is working hard to protect and restore bats’ access to water. This precious liquid is crucial for all living things hoping to live out their maximum potential lifespan.

about the author

Karin Akre, Ph.D.

Science Writer

Dr. Karin Akre joined Bat Conservation International as our Science Writer in September 2023. She supports scientific research to inform conservation actions for bats by creating engaging and informative content for diverse audiences. She contributes to scientific articles, grant proposals, and outreach materials.

Karin has over 20 years of experience in science writing and research. She has published scientific articles on the evolution of behavior, and she taught animal behavior and conservation courses at the University of Texas, Austin and Hunter College. Prior to working for BCI, she wrote and edited K-12 science textbooks, encyclopedia articles, and science-based television scripts. Her writing translates complex scientific information into language that can educate and inspire audiences to increase their awareness of conservation topics.

Karin received her Ph.D. in ecology, evolution, and behavior from the University of Texas, Austin and a bachelor’s degree from Harvard University in psychology and biology.

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