Still have questions? Dr. Bryan Wallace, Conservation International’s resident sea turtle scientist, and his colleagues are here to help! Click here to send Bryan your unanswered queries. Each month, he’ll select one question to explore in greater depth with his friends, and post their findings here for all to see.
The question of how old sea turtles get is important and seemingly simple, but one we actually don't know the answer to.
What we do know is that sea turtles certainly live a very long time, probably similar in lifespan to humans. Depending on the species, sea turtles reach sexual maturity in 10-15 years (for ridleys) to 30-40 years (for greens) after emerging from their nests as hatchlings. Because it takes them so long to reach adulthood, we know that sea turtles must spend decades as adults to reproduce long enough to replace themselves (and their mates) in the population.
One of the main methods that scientists use to infer age in sea turtles is called skeletochronology. This method is similar to counting tree rings, except that instead of layers of wood deposited annually by a growing tree, a turtle's bone—particularly the dense humerus in a sea turtles front flipper—deposits rings as well, supposedly on an annual basis. Skeletochronology has been used to determine age at maturity as well as ages of individual turtles, and has been shown to work well in some species (e.g., ridleys), but not as well in others (e.g., leatherbacks).
So, while Crush from 'Finding Nemo' was right that sea turtles live a long time, we're still not sure about the actual number.
Bryan Wallace, PhD, is the Science Advisor for the Sea Turtle Flagship Program at CI and is Adjunct Assistant Professor in the Nicholas School of the Environment at Duke University. His work deals with the applications of sea turtle ecology research to pertinent conservation issues. Specifically, Bryan’s research focus has been on how the interactions between sea turtles and physical and biological conditions of their environments affect their physiology, ecology, life history, and population demography. He has worked extensively in Latin America and the U.S. on sea turtle research and conservation projects. He speaks Spanish fluently, has coordinated teams of volunteers on field projects focusing on sea turtles and other species. He has served as a program co-chair, regional travel chair, and student judge at multiple International Sea Turtle Symposia. He received his PhD from Drexel University (2005), and was a post-Doctoral Researcher at the Duke University Marine Lab (2005-2007).