Dying Without Wings
Apr 16, 2014
When looking for the secret to a long life, the answers may be found by surveying the skies, scanning the trees and peering down a few choice holes in the ground. This is according to scientists from Trinity College Dublin, who believe they know why animals spending their time in these environments live longer than is expected for other species of similar sizes.
We have always been fascinated by the concept of a lifespan, and are still searching for the elixir of life today. Recently, the pursuit of ‘cures’ for human ageing has looked to the animal kingdom, especially within vertebrates, where lifespans vary from just eight weeks in the pygmy goby to an astonishing 211 years in the bowhead whale. Differences in lifespan usually relate to body size, with bigger species living longer. However, the pattern doesn’t hold for everyone in the animal kingdom, which made the scientists ask why.
Their research, just published in the high-profile journal Proceedings of the Royal Society B, provides new insights into the evolutionary reasons that underpin why certain species, such as bats and naked mole rats (as picture-imperfect as their name suggests) enjoy relatively long lifespans.
By looking at the maximum lifespan of more than 1300 birds and mammals, the authors found that species that live in trees or burrows, or that possess the ability to fly, lived far longer then expected for their body size. They believe that these modes of life result in a reduced risk of death from external forces, such as being eaten by predators or starving due to drought. This evolutionary safety net means natural selection has pushed these species to invest more effort into living longer.
“These results help explain the unusually long life spans of many birds and bats, as such species can easily avoid predators or poor weather. Long-ranging sea birds, such as the albatross, provide a great example,” explained lead author and PhD student in Zoology at Trinity, Kevin Healy.
He added: “Our findings also allow us to more accurately identify species with extreme lifespans, which pushes us to try to understand their secret(s). For example, while bats were thought to have unusually long lifespans, our results show that only a small group of them actually live longer than expected once we have taken into account the benefit they get from being able to fly. When it comes to lifespan, most bats can really be thought of as furry birds.”
Assistant Professor in Zoology, Natalie Cooper added: “Our results show that if we want to uncover the secrets of long life, we should expand our search far beyond bats and naked mole rats!”
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