A small bat being held in a human hand. Photo by Jacopo Werther. Bats comprise 20% of all mammal species and most are remarkably long-lived — on average about three times as long as predicted for their size. Bats, like birds, couple high metabolic rates with exceptional longevity in the wild.

Brandt’s bat (Myotis brandtii) is the longest-lived bat species documented so far. It weighs 7 grams — a bit less than three pennies — based on mark-recapture studies it has a lifespan of at least 41 years in the wild. You can read more about bat lifespan in the Successful Aging library.

Photo: Jacopo Werther
Naked mole rat next to a soccer ball. Image: Mehgan Murphy, Smithsonian National Zoo. Naked mole-rats (Heterocephalus glaber) are mouse-sized rodents from South Africa. They live in large subterranean colonies with a single reproductive female and several reproductive males. The oldest recorded naked mole-rat was trapped as an adult in the wild and lived in captivity for 30 years. Read more about these animals in the Successful Aging library.

Photo: Mehgan Murphy/Smithsonian National Zoological Park