Why do some organisms live longer than others? It’s a question that drives biologist Kevin Healy wild. As a Research Fellow in the School of Natural Sciences at Trinity College Dublin, Healy searches for the traits that help some species outlast others — or — explanations for evolutionary superpowers. At TEDxUCD, Healy introduces some of the animals he studies, from naked mole-rats to microbats, and makes a case for getting to know them better.
Overall, there’s a few cardinal rules to aging, Healy says. For one, bigger things usually live longer than smaller ones. The smallest fish in the world, the seven-figure pygmy goby, for example, lives only an average of 59 days, Healy says, while a Bowhead whale can live over 200 years. Humans usually live longer than mice; mice usually live longer than insects; and so on.
Of course, there are exceptions to the rule — and that’s Healy’s bread and butter. Two of Healy’s favorite rule breakers are the bat and the naked mole-rat. Most bats live about 20 years, he says, while the similarly-sized house mouse lives four years at most. But naked mole-rats beat them both — tapping out at 31 years old.
“They’re the same size, yet [the naked mole-rat and the bat] are living orders of magnitude longer [than mice] … How can they get around aging?” Healy asks.
The answer is what he’s searching to find. The hottest theory is that the two creatures are great at avoiding predators, so that gives natural selection more time to select the traits that best enable longevity, Healy says. “A mouse is never going to be worried about cancer as much as it’s going to be worried about cats. But the naked mole-rat and the bats don’t have to worry about cats,” he says. “The naked mole-rats live in tunnels that are really well protected and bats can simply fly away [from predators], so they live longer naturally and natural selection lets them live longer again.”
Despite how intriguing this theory is, studying and testing it is not very easy, Healy says. Animals exhibit a massive amount of traits and behaviors, and linking these to mortality outcomes takes masses of data. To single out one impressive trait, you have to scour through seemingly endless evidence of others. Healy wants to simplify that process.
“Evolution might have solved [aging] problems again and again in many different species, but this is still a very difficult thing to know,” he says. “I [am interested in] gathering not just more information, but better information. Species aren’t just defined by how long they live; all sorts of other interesting things are going on there … [we wonder] ‘Where is their mortality rate the highest?’ ‘When do they reproduce?’
“By [collecting this data and] developing these better, more complex models, we can try to figure out what is it that is really driving the evolution of these really odd species and their amazing ability to circumnavigate aging … If we can understand what makes [these creatures] so odd and so special, we can go a long way toward understanding how aging works and better understand how to fix it ourselves.”
His solution? Databases. Really, really complex databases. He and colleagues at Trinity College Dublin have developed COMADRE and COMPADRE, two databases filled with masses of data about animal and plant species, respectively.
COMADRE contains data on 1,200 animal species, comprised of “demographic, taxonomic [and] biogeographic” information, as well as the animals’ conservation status. The database is still growing, and with it, our knowledge of aging and the world.
For more information, watch Healy’s whole talk below: