Everybody knows that tortoises live a long time and they are a long-time commitment pet, but most tortoise owners including myself only know the lifespan of very few tortoise species, usually the most popular ones. So I decided to do some research about how long do tortoises live, here is what I found out.
How long do tortoises live? Tortoises have a very long life compared to other reptiles and animals. Most aquatic and land tortoises and tortoises live around 40 years, but there are certain species that will live even longer than that, some of them even reaching ages over 100 years old.
By making an average of the lifespan of all tortoise species, 40 years is a good estimate. But that is just an average and a lot of tortoise species will live longer than that and a few of them will have a shorter life. In the rest of the article, I am going to tell you how long they live in the wild, how long they live as pets, why there is a difference, and how to tell the age of a tortoise, among other things.
How Can You Tell the Age of a Tortoise
Before talking about tortoise ages it will be better if you learn how the age of a tortoise is determined.
The Counting Method
The age of many hard-shelled tortoises, like red-eared sliders, painted tortoises, musk tortoises and snapping tortoises, and many other species, can be estimated with a margin of error of about 6 to 7 years by counting the number of growth annuli. Growth annuli are small groves on each of the scutes of the shell. This is very similar to the way you will count the rings of a tree to find out his age because each ring or growth annuli in the case of the tortoise will indicate one year. During periods of inactivity, like the winter, the scutes of a tortoise will grow slower, or they won’t grow at all in some cases, and during spring or summer, the scutes will grow faster, resulting in a ring-like pattern on the scutes.
The counting method still has some flows. One of them is that it can only be used on hard-shelled tortoises, since the shell of soft-shelled tortoises works in a different way, there won’t be any growth annuli to count. Another problem with this method is that it won’t work well with pet tortoises, if you keep your pet tortoise at a constant temperature year-round there won’t be any difference in the speed at which the shell grows so there will be no annuli to count. Rings can also be an inaccurate measure of the age in tortoises in which the shell has become worn and smooth because the rings will be faint or they will disappear completely.
Some tortoise species like the mud tortoises from North America will reach maturity when they are around 6 or 7 years old, at which point their growth will slow down considerably. Mud tortoises will still grow after that point but a lot slower, and during periods of slow activity, like the winter, they will grow even slower or they won’t grow at all. At this point, their growth annuli will become very compact and it can be easy to get them mixed up because they will be very compressed.
Another factor that can influence the ring counting method is the environment, more exactly the unusual environmental conditions. For example, if a certain area has a lot of food at the beginning of the year and then a drought happens out of nowhere and the food is gone this will make the tortoise enter in a long period of inactivity that it normally wouldn’t. And after the drought is over food starts to reappear the tortoise will enter a period of full activity in which the shell will once again start to develop at full speed. Events like those can create fake growth annuli that are almost indistinguishable from real ones.
So overall this method has its flaws and it’s not always the best for scientific research, but it’s a great way to get an estimate of the age of a tortoise, after all it will be very obvious if a tortoise has over 50 years or under 20 no matter how many false growth annuli it has. So if you find a tortoise in the wild you can easily get an estimate of how old it is using this method.
The Size Method
This method usually is not very precise and it requires a lot of prior knowledge, so it’s not the best option for most people, but it’s one possibility so I am going to tell you about it
Compared to other animals, tortoises grow very slowly, some species will grow faster than others but in general, they will grow very slowly. The fact that they grow this slow will help a lot of people with knowledge and experience with tortoises determine the age of a tortoise. If you have experience working with tortoises or if you had one yourself, you will be able to tell apart from a 6 months tortoise from a 2-year tortoise from a 10-year-old tortoise.
At first sight, this method will seem more like guessing, and that it’s true, but at long as it’s a person with good knowledge about tortoises that guess will be pretty close. As you gain more experience the closer you will get to the actual age.
Like all methods, this one has its flaws. The most obvious one is that if you have little to no knowledge you will be way off with your guess. Another one is that even if two tortoises belong to the same exact species they will grow at different rates based on their environment. This is why you can usually get good results with this method only if you apply it to well-researched species like slider tortoises and painted tortoises, and if you know the area where they live very well.
So overall this is not the best method and it can only give good estimates if you have good knowledge. This method is usually not used for scientific researches, but researchers will occasionally take notes and they will estimate the age of a tortoise using this method if they didn’t have the chance to get close enough.
Mark-recapture
This method is mainly used by biologists to determine the age of a tortoise, and not by normal people, so please don’t try this with any tortoise, you could hurt them in the process if you don’t know what you are doing.
When using this method tortoise biologists will use a file or a small drill to carefully place a mark on the shell of a wild-caught tortoise. Those marks are usually small, so the tortoise won’t be affected by it at all, but noticeable at the same time to make sure that the measurements will be accurate.
After the mark is placed the tortoise will be released in the wild from where it came. After a period of time, these tortoises will be caught back and their shells will be studied to see their evolution and how did the mark age compare to the counting method. After that tortoises are free once again to go back into the wild.
Studies that use this method are usually long-term and can help determine the age a tortoise can reach. For example, one study that used this method was conducted on multiple tortoises that belonged to the following species: slider tortoises, eastern mud tortoises, and painted tortoises. When they were first caught the tortoises were estimated to be between 6 and 10 years old. The next part of the study took place 25 years later. A lot of the tortoises were found, this proved that a lot of them can live more than 30 years. There are a lot of factors that can influence the lifespan of a tortoise, especially in the wild, but a study like this definitely proves that a lot of those tortoise species could live that long.
Studying the Skeleton
The last method that you can use is again better left for biologists and people that know what they are doing.
As the name implies this method requires the biologists to study the skeleton of a tortoise to find out the age. Neither this method is 100% accurate but it can give good estimates, especially if there is no other way to find out.
This method is mainly used for fossils and on the skeletons of extinct species since there is no reason to use it for a tortoise that is still living.
The exact process that the skeleton will go through can differ since there are a lot of methods to study the bones so i am not going to go into details any further for this method, the only thing that you have to know about this is that this is the way they determine the age of tortoise fossils and extinct species of tortoises in general.
How Long Do Tortoises Live in the Wild ?
As I said at the beginning of the article 40 years is generally accepted as the average age a tortoise can reach. Why are 40 years generally accepted and there is no exact number? Because despite the fact that there are numerous claims of tortoises reaching hundreds of years, true documentation is not always forthcoming. Even claims by biologists have to be looked at with a little skepticism unless a clear chain of custody exists for the specific tortoise. The fact that they don’t always have the complete documentation of a certain tortoise doesn’t mean that they are lying or their studies are bad, it just means that there could be errors and that their study might not be 100 percent accurate.
Another problem with determining an exact number is the fact that a lot of tortoises will certainly live over or close to 100 years, and there wasn’t enough time to completely study the entire lifespan of such an old tortoise. You have to take into consideration that the study of the tortoise wasn’t always a topic that interested biologists when there were more pressing matters at the time that needed research. And such a long study will have to be done by multiple generations of biologists.
And as I’ve told you the methods used to determine the age are not always flawless. This can also influence the studies that were made. But even if studies can have small flaws in them, if multiple studies show that the average lifespan of tortoises is around 40 years that number becomes generally accepted.
Studies done on wild tortoises can be a lot harder than on captive tortoises. If you want a study to be done on wild tortoises you have to interfere with the tortoise as little as possible, so keep an eye on a single tortoise can be really problematic.
Even if biologically speaking, tortoises can reach very long ages, when they are in the wild there are a lot of factors that will shorten their lifespan. The first and probably the most decisive one are predators, even if a tortoise is able to live for 100 years, if most tortoises of a certain species are eventually caught by a predator until they reach 40, the general lifespan of that tortoise species will be considered 40. But their maximum biological age will still be 100. Even if predators don’t always inflict grave wounds, the small ones that they inflict can drastically alter the lifespan of the tortoise.
Another thing that will greatly influence the maximum age a tortoise can reach is represented by the environmental conditions. If an area that is inhabited by a large number of tortoises goes through a drought for several years, or an earthquake drastically changes the landscape, all the tortoises will be negatively affected by that event and their lifespan will be shortened.
This is why overall is hard to determine how long tortoises live and why it’s very hard to know the exact age a tortoise can live in the wild. But now let’s talk about some studies and some interesting numbers that they provided about how long tortoises can live.
Two long-term studies took place in southern Michigan, one at Sheriff’s Marsh associated with Michigan State University’s Kellogg Biological Station, and the other took place of the University of Michigan’s George Reserve, both studies took an interest in the lifespan of tortoises. Those studies offered unquestionable evidence that some tortoise species can live a very long time in the wild.
An adult Blanding’s tortoise was at least 25 or more years old, and many more adult tortoises were captured and marked during the ’50s in the George Reserve and during the 60’ in the Sheriff’s Marsh. Those same tortoises were captured again during the 2000s and inspected. A lot of the Blanding tortoises were found, including the one that was believed to be around 25 years old, and others that were close to that same age. This study showed that a lot of tortoises can live more than 60 years in the wild if the conditions are good. At the moment some of those same tortoises still live there, but until all of them are captured again for inspection we can’t say that they live to be 70 or 80 years old.
The oldest tortoise known to lay eggs in the wild is a Blanding’s tortoise in Minnesota. The event was recorded and documented by biologists that say that the tortoise is more than 75 years old.
The Longest Living Tortoise Species in the Wild
Overall the longest living tortoise species in the wild is the Galapagos tortoise, which usually reaches ages close to 200 years.
The Galapagos tortoise is the species that live the longest in the wild, most of them reaching ages close to 150 years and some of them getting close to 200 years. This interesting thing is that the Galapagos tortoises don’t necessarily have the biggest lifespan, but they live in very remote islands, and after they reach a certain size there are no predators that are able to present a threat to them, at which point they basically have no worry.
So the secret of the long lifespan of Galapagos tortoises is not necessarily the fact that they can live long, but rather their size which makes them immune to predators, and the fact that they live on isolated islands.
Fun fact #1: Galapagos tortoises are not all the same, they inhabit multiple islands in the Galapagos, and every island has its own subspecies that have small characteristics that differentiate them from the rest.
Fun fact #2: They spend most of their time sleeping, usually for very long periods of time between 15 and 18 hours.
Fun fact #3: Galapagos tortoises got their name from Spanish sailors who named the archipelago Galapagos, which comes from the Spanish word Galápago which means tortoise.
How long do tortoises live as pets ?
40 years is again a good estimate of how long tortoises will live as pets, but the reason is a little different.
When tortoises live as pets or in captivity in general they won’t have to worry about predators or lack of food anymore, so this should drastically increase their lifespan and the average should be higher than 40, but there are some very good reasons why the number stays the same.
The first reason is that not all tortoises that live in the wild are suitable to be pets, for example, the Galapagos tortoises that we talked about earlier will never be a pet, leaving aside that they are a vulnerable species ( that means that they are not endangered but they are getting close to that point ), you will need very huge amounts of space and a lot of food to feed them. The same problems appear when it comes to a lot of tortoises so a lot of species are eliminated from the list of possible pet tortoises, and a lot of those species are some of the longest living ones.
The amount of effort that you put into taking care of your tortoise will also influence how much time they will live. Unfortunately, a lot of tortoise owners don’t know exactly how to properly take care of their tortoises, some of them will learn, but some of them will not know that they are doing things wrong until is too late. Even if tortoises don’t require that much maintenance or equipment, not having them can badly influence their health.
There are also diseases like shell rot that are more likely to develop when the tortoise is in captivity than when the tortoise is in the wild, even if it’s treated it will have an impact on the health of the tortoise.
Most tortoise species that are pets are usually small or medium-sized. Those tortoises don’t live as long as their bigger relatives, so this will put a very important noticeable cap on the maximum life expectancy of captive tortoises.
Tortoises that live in the zoo are usually taken care of by specialists, or at least people who are instructed by specialists so they will usually reach the maximum of their lifespans. Zoos are also able to house bigger species of tortoises that most people won’t be able to keep as pets in their homes. So in general zoos will greatly increase the amount of time that a tortoise will live in captivity.
Taking into consideration all the things that I’ve mentioned above it’s easy to see why the average life expectancy of tortoises that live in the wild and tortoises that live in captivity is similar, both have their advantages and disadvantages, and if you add all of them up you will get the same result.
The longest living tortoise species in captivity
The Aldabra giant tortoise is the longest species of tortoise in the world, some specimens reaching the age of 255 years old.
Adwaita is the name of the Aldabra tortoise that reached the age of 255 years. Adwaita died on 22 March 2006 at the age of 255 years, in Alipore Zoological Gardens, Kolkata, India.
The Aldabra tortoises are able to live longer than the Galapagos tortoises overall, but due to the nature of their environment, they don’t usually reach those ages.
Adwaita didn’t exactly die of old age but because his shell got cracked in 2005 and then developed an infection that lead to his death. It’s not sure why the crack appeared, no incidents have been reported at the zoo and the caretakers were most definitely very careful with the oldest tortoise in the world. It could be that this can happen after a tortoise reaches a certain age.
The could be tortoise species that can live longer than that but at the moment none are known. And the fact that we will need at least 255 years to know if this is possible isn’t very encouraging.
The Oldest Living Tortoise in the World
At the moment the oldest living tortoise in the world is a Seychelles giant tortoise that at the moment is 186 years old.
Jonathan is the name of the Seychelles giant tortoise that is the current longest living tortoise in the world, and also the longest living terrestrial animal in the world. He lives on the island of Saint Helena, a British Overseas Territory in the South Atlantic Ocean, and he is owned by the Government of Saint Helena.
At the moment Jonathan is healthy and living a peaceful life, if things continue to go this way for him, in about 70 years he will become the oldest living tortoise in the world of all time.
How to make sure that your tortoises will live a long life
There are a lot of things to say about this subject, but the most important things that you have to do are:
- Making a good habitat, this includes getting the proper gear and making sure that it’s completely safe for them
- Control the temperature, tortoises are cold blooded reptiles so the temperature of their environment is very important for them
- A balanced diet, making sure that they have a good and balanced diet is very important for every animals lifespan, and this includes tortoises too
Those are the essential 3 things that you have to keep in mind. If you want to know more about how to properly take care of a tortoise then browse the rest of the articles on this site, especially the Care Guides page, and the Recommended Gear page, on those two pages you will find all the information you will need.
Why Do Tortoises Live so Long ?
Tortoises live so long because they are cold-blooded animals and they have a slow metabolism.
When you hear the word metabolism you might be thinking about how this affects our weight based on how much we eat. For example, a person who has to eat constantly to keep from losing weight may say they have a “fast metabolism,” while a person who eats only a little and still gains weight may say they have a “slow metabolism”.
But metabolism isn’t something unique to humans, scientifically/biologically speaking metabolism just refers to the sum total of the biochemical reactions that take place in an organism’s body. So every living thing on this planet has a metabolism, this even includes plants, bacterias, and other kinds of small living things.
In general, the metabolic rate refers to how fast or slow, in the case of tortoises, the body burns fuel from food to keep the organism running. The metabolic process is at its base a process of extracting energy from food and passing it to the rest of the body, but like all energy exchange processes, this one is also not perfect and as a result, the energy that is not transferred to the organism is released as heat.
The energy that is released as heat is used by a lot of animals to regulate their body temperature. Those animals are called endotherms, we humans also use this heat to regulate our body temperature so we are also endotherms.
Tortoises on the other hand are what we call ectotherms, this means that they don’t use that heat to regulate their body temperature, but instead their body temperature adjusts after the temperature of the surrounding environment.
Endotherms tend to have high metabolic rates and high energy needs, thanks to their maintenance of a constant body temperature. Ectotherms size tend to have much lower standard metabolic rates and energy.
An animal’s metabolic rate determines how much food it must consume to maintain its body at a constant mass. If an animal doesn’t eat enough food to replace the energy it uses up, it will start to lose body mass and after some time there can appear big health problems. Since tortoises have a slow metabolism they don’t need that much food to survive, this is one way that their slow metabolism helps them. Even if they don’t need too much food to survive that doesn’t mean that if they don’t eat for long periods of time their health won’t be affected, it just means that they can live longer without food than an animal with a high or normal metabolic rate.
In the wild, a lot of tortoises will go into hibernation during winter when there is little food available and the temperatures are very low. During this time their metabolism becomes even lower and they can last enough time without food until winter passes.
Because their body uses less energy to maintain itself, the organism of a tortoise will also “degrade” slower. The organism of almost every living thing on this planet will start to degrade as time goes by. In humans, you can see this very clearly when you compare a 20-year-old person with a 70-year-old person. There are a lot of things that can affect how a person will be when they get old, but no matter what they will do their body will start to “degrade” and they will become old, and health problems will start to appear. Tortoises go through the same process, but since their metabolism is a lot slower, their body isn’t affected at the same rate.
You can compare the body of a living being that has a metabolism with a car that has an engine, no matter how careful you use it, as long as you put fuel into it and you use it it will start to have small problems over time. This is a very simplistic way to explain things but I wanted to add this just to have a simpler way of looking at things.
So overall tortoises have a slow metabolism that doesn’t require too much food to maintain itself and they burn energy at a very slow pace and this doesn’t affect their body as much as it does to other animals that have higher metabolic rates.
List of Tortoises Lifespan
Here is a list of some tortoise species and their average lifespan:
Tortoise Name: African Spurred tortoises
Average Lifespan: 55 years
Tortoise Name: Russian tortoise
Average Lifespan: 40 years
Tortoise Name: Indian Star tortoise
Average Lifespan: 50 years
Tortoise Name: Greek tortoise
Average Lifespan: 40 years
Tortoise Name: Aldabra tortoises
Average Lifespan: 60 years
Tortoise Name: Gopher tortoises
Average Lifespan: 40 years
Conclusion
I hope you now have a better understanding of why tortoises live so long, and how long they live. If you have any questions about this subject or anything related to tortoises please don’t hesitate to ask them in the comment section, I will answer them as soon as possible.
Hello,
If you enjoy the content that we create, please consider saying a "Thank You!" by leaving a tip.
Every little bit can help us tremendously in continuing to create quality content that helps turtle and tortoise owners around the world.
We really appreciate the kindness and support that you show us!