WHY DO TURTLES LIVE SO LONG?
By Whit Gibbons
Q: I am in fourth grade at a primary school in China and am writing a science story for my English class about turtles having a longer lifespan than most other animals on Earth. Please help me by answering these questions. I did some reading and found that turtles can live up to 25 years or longer. Why do turtles live so long? What factors help them have a long life?
A: Well-developed body armor allows many adult turtles to persist in nature. Although eggs and baby turtles are highly vulnerable to predation, once hard-shelled turtles reach adulthood, they are protected from most natural predators. American and Chinese box turtles have moveable plates that let them close their shell completely, making it difficult for most animals to eat them. Also, many turtles in America and China are aquatic; they are experts at hiding from would-be predators in the mud at the bottom of a lake or river. Most turtles show few signs of senility. If they can avoid being killed, many reach an old age.
Q: Could pet turtles also have a long life like turtles in the wild?
A: Some wild turtles studied in long-term research programs are known to live for many years. A female Blanding’s turtle in Minnesota was documented to lay eggs at 75 years old. Captive turtles are known to have lived even longer. Pet turtles do not face hazards confronted by wild turtles, such as extreme weather conditions, especially drought or subzero temperatures. Nor are they subject to predation.
Q: What is the longest surviving turtle species in the world?
A: Some of the longest age records are of turtles kept in zoos. A few individual pet owners also report remarkable longevity records. Matt Aresco in Florida has a gopher tortoise he acquired in 1964, making it at least 55 years old. Riverbanks Zoo in Columbia, and the San Diego Zoo have Galapagos tortoises known to have been adults in 1928, making them almost certainly more than a century old.
Q: What can humans learn from turtles about having a longer life expectancy?
A: Humans have a lot to learn from all animals and plants through medical research and behavioral observations. One line of study might be to determine what genetic traits keep some turtles from showing typical characteristics of senility. With our current knowledge of genetics, findings might emerge that are directly applicable to humans.
Q: What is the role of turtles in maintaining a balanced ecosystem?
A: A recent scientific paper noted several significant ecological roles turtles play, such as dispersing seeds, enhancing germination of seeds, and recycling nutrients in terrestrial and aquatic systems.
Q: How can humans protect turtles?
A: Turtles, like the rest of the world’s wildlife, are declining. Many verge on extinction. Human overpopulation is leading to more habitat degradation than the world has ever known. Turtles are also subject to great losses because of poaching and illegal pet trade activities. Preserving natural habitats and controlling pet trade smuggling would help protect turtles globally.
Q: Are turtles in danger of becoming an endangered animal like the panda?
A: Some of the 360 species of turtles are more endangered than pandas whereas a few are less so. Each must be considered on a case by case basis.
Q: What were the ancestors of turtles?
A: Scientists continue to debate what the oldest turtle ancestors were. Turtle fossils with shells and skeletons similar to modern turtles have been found in sedimentary rocks more than 200 million years old, when dinosaurs still roamed the earth.
Q: Please suggest a book I might read for my research about turtles.
A: “Turtles: The Animal Answer Guide” (2009) published by Johns Hopkins University Press is an easily readable book that answers many questions about turtles.
Dr. Whit Gibbons is Professor Emeritus of Ecology, University of Georgia, and former Head of the Environmental Outreach and Education program at the Savannah River Ecology Laboratory (SREL). He currently serves on ARC's Board of Directors.