No one can escape aging, but some species live much longer than others. For example, Myrtle, the green sea turtle housed in the Giant Ocean Tank of the New England Aquarium, is approximately 95 years old and thriving. Two independent research groups have looked across several species and discovered some of the reasons why turtles barely age.
Researchers from the University of Southern Denmark evaluated survival data from amphibians and reptiles housed in zoos. They found barely any evidence of aging in 75% of chelonians, the animal order that includes turtles, tortoises and terrapins. Furthermore, the aging rate, or the rate at which the risk of mortality increases across age, is considerably slower in the chelonian group compared to mammals. Although this group studied populations under protected environments, their conclusions were backed by another group, led by scientists at Penn State, who analyzed field data from 77 species of reptiles and amphibians, including 14 species of chelonians. They showed correlations between the impressive longevity of turtles and tortoises and their slow-paced life. Animals who first reproduced later in life lived longer. Additionally, physical protection conferred by their bony shells also increases their longevity. Generally, all species with protective armor outlived and aged slower than unprotected species.
These are the largest studies to date on aging and longevity in reptiles and amphibians. These studies highlight the links between the protective shells, life-history tactics, and extended lifespan of chelonians, including our Boston-based friend, Myrtle. Comparative studies can give novel insight into the limits and evolutionary influences on aging rate and longevity.
Rita Da Silva is an Assistant Professor at the Interdisciplinary Center on Population Dynamics at the University of Denmark. Fernando Colchero is an assistant professor in the Department of Mathematics and Computer Science and the Interdisciplinary Center on Population Dynamics at the University of Denmark. Beth Reinke is an Assistant Professor at the Department of Biology at Northeastern Illinois University. David Miller is an Assistant Professor in the department of Ecosystem Science and Management at Pennsylvania State University.
Managing Correspondent: Isle Bastille
Press articles: ”Secrets of aging revealed in largest study on longevity, aging in reptiles and amphibians,” ScienceDaily
“How ubiquitous is aging in vertebrates?,” Science
Original Journal Articles: “Slow and negligible senescence among testudines challenges evolutionary theories of senescence,” Science
“Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity,” Science
Image credit: Isle Bastille, science photographer @mindful_photon on Instagram