Tortoises are widely recognized for their exceptional longevity, often living far beyond the lifespans of most other creatures on Earth. Their remarkable ability to endure for decades, or even centuries, consistently fascinates observers. This enduring presence makes understanding their long lives a topic of considerable interest.
Lifespan Across Different Tortoise Species
The lifespan of a tortoise varies significantly depending on its species. Giant tortoises, such as the Galápagos and Aldabra, are known for their extreme longevity, often living over a century. Galápagos tortoises can surpass 100 years in the wild, with some individuals in captivity reaching up to 177 years. Aldabra giant tortoises live 150 years or more, with some exceeding 200 years.
Sulcata tortoises live between 50 and 150 years. Russian tortoises live between 50 and 100 years. The Greek tortoise has verified lifespans exceeding 100 years in captivity. However, in the wild, Greek tortoises often do not live beyond 30 years due to factors like predation.
Methods for Estimating Age
One popular, yet unreliable, method for estimating a tortoise’s age involves counting the concentric rings found on each scute, the plates covering its shell. These “growth rings” form during periods of rapid growth. However, this method is imprecise because a tortoise might develop several rings in a single year, or none at all during lean times or illness. The rings denote growth periods, not annual increments, making them an inaccurate chronological marker. For adult tortoises, shell wear can further obscure these rings, making accurate counting difficult.
Other indicators can provide a rough estimate of a tortoise’s age. A tortoise’s size offers clues, as larger individuals of the same species are generally older. However, size is also influenced by diet and health. The texture and appearance of the shell and skin can also suggest age; older tortoises often have smoother, more worn shells and more wrinkled skin. Ultimately, the only accurate way to determine a tortoise’s age is to know its hatching date.
Biological Reasons for Longevity
The remarkable longevity of tortoises is largely attributed to several unique biological adaptations. A significant factor is their extremely slow metabolism, meaning they burn energy at a much lower rate compared to faster-moving animals. This reduced metabolic activity lessens oxidative stress and cellular damage, processes that are major contributors to aging in many other species. Their slow energy expenditure also allows tortoises to survive extended periods without food or water, enhancing their resilience to environmental challenges.
Tortoises also possess highly efficient cellular repair mechanisms that contribute to their extended lifespans. They have advanced DNA repair systems, which help to effectively mend genetic damage and prevent the accumulation of mutations that typically lead to age-related diseases. These reptiles have evolved robust mechanisms to suppress tumor formation, giving them resistance to cancer. Some tortoise species also exhibit a slower rate of telomere shortening, which are protective caps on chromosomes, further preserving cellular function over time.
Famous Elderly Tortoises
The longevity of tortoises is exemplified by several well-known individuals who lived for a long time. Jonathan, a Seychelles giant tortoise residing on the island of Saint Helena, is recognized as the oldest living land animal. Born around 1832, he is estimated to be 192 years old as of 2025, having arrived on the island in 1882 already fully mature.
Another example is Adwaita, an Aldabra giant tortoise who lived at the Alipore Zoological Gardens in Kolkata, India. He passed away in 2006 at an estimated age of 255 years, believed to have been born around 1750. Harriet, a Galápagos tortoise, lived to an estimated 175 years. She died in 2006 and is believed to have been collected by Charles Darwin during his voyage on HMS Beagle in 1835.