'Average' - not 'longest' life expectancy of Tortoises

[niraj]

Hello,

We have all read about the longest living tortoises of different species. However, there is little information available which can be considered authentic with regard to average life expectancy of tortoises. Interestingly, information is available mostly is only on one particular animal of that species which may not depict the true picture. I am listing a few famous tortoises for the purpose of this discussion:

1) Adwaita (A. Gigantea) - 255 years - unverified (about 130 years - verified)

2) Harriet (Galapagos) - 175 years

3) Tu'i' Malila (Geochelone Radiata) - 188 years

4) Timothy (Testudo graeca) - 160 years

5) Jonathan (Seychelles giant tortoise) - 186 years (alive)

6) Lonesome George (Chelonoidis abingdonii) - 101 years

On bare reading of the above examples, no two tortoises of one species appear (atleast in data available). I request the experts here to shed some light on whether this means that the above were exceptions and on an average, animals of their respective species do not live around their age of atleast close to their ages. Also, if there is any research available wherein lifespans of more than one animal of a particular species have been examined.

Thank you.

 

[orv]

I am unable to be of authorative help as to the average lifespans of the various species of tortoises, however if some of our forum members are able to share the lifespans of their own tortoises, perhaps a mean may be found. I owned a male California Desert Tortoise, who I received as an adult of, say at least 20 years of age, and he lived with us until his death 61 years later. We currently care for a female, again coming into our care as an adult who has now lived with us for 48 years as is still in good health. We have one of the above pair's progeny who's 34 years of age. Perhaps others will add to these numbers to form a graph.

 

[niraj]

I am unable to be of authorative help as to the average lifespans of the various species of tortoises, however if some of our forum members are able to share the lifespans of their own tortoises, perhaps a mean may be found. I owned a male California Desert Tortoise, who I received as an adult of, say at least 20 years of age, and he lived with us until his death 61 years later. We currently care for a female, again coming into our care as an adult who has now lived with us for 48 years as is still in good health. We have one of the above pair's progeny who's 34 years of age. Perhaps others will add to these numbers to form a graph.

Thank you very much.

 

[orv]

By the way . . . WELCOME to our forums!

 

[Ramsey]

Interesting topic. I think you will find that it will be very difficult to get clinical data on this, due to the longer lifespans tortoises have. I suspect there simply isn't enough documented data.

I remember asking one of my vets the lifespan question, and I was told the average in the pet trade is 20-30 yrs.

This is, however, different than those with managed professional care from your list above. I know the Galapagos tortoises at our local zoo are over 100 yrs old, and they are in excellent shape.

 

[niraj]

A great effort is made on determining the average lifespan of parrots.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3289156/

On studying the same ( see Table 2), it appears that there is a huge difference between the example of a parrot living the longest and the average / median of other birds of the same species. For example, the highest recorded lifespan of a Moluccan Cockatoo is 92 years while the average / median is a shockingly low - 11 years. The same is true for most other species.

Of course, there cannot be a comparison between parrots and tortoises. But, the purpose of citing the same is to show that many a times, popular belief is misleading. A particular tortoise may have lived for over 100 years, but do most others in there species reach anywhere close?

 

[niraj]

By the way . . . WELCOME to our forums!

Thank you

 

[niraj]

Interesting topic. I think you will find that it will be very difficult to get clinical data on this, due to the longer lifespans tortoises have. I suspect there simply isn't enough documented data.

I remember asking one of my vets the lifespan question, and I was told the average in the pet trade is 20-30 yrs.

This is, however, different than those with managed professional care from your list above. I know the Galapagos tortoises at our local zoo are over 100 yrs old, and they are in excellent shape.

Thank you very much.

 

[niraj]

Hello,

We have all read about the longest living tortoises of different species. However, there is little information available which can be considered authentic with regard to average life expectancy of tortoises. Interestingly, information is available mostly is only on one particular animal of that species which may not depict the true picture. I am listing a few famous tortoises for the purpose of this discussion:

1) Adwaita (A. Gigantea) - 255 years - unverified (about 130 years - verified)

2) Harriet (Galapagos) - 175 years

3) Tu'i' Malila (Geochelone Radiata) - 188 years

4) Timothy (Testudo graeca) - 160 years

5) Jonathan (Seychelles giant tortoise) - 186 years (alive)

6) Lonesome George (Chelonoidis abingdonii) - 101 years

On bare reading of the above examples, no two tortoises of one species appear (atleast in data available). I request the experts here to shed some light on whether this means that the above were exceptions and on an average, animals of their respective species do not live around their age of atleast close to their ages. Also, if there is any research available wherein lifespans of more than one animal of a particular species have been examined.

Thank you.

An interesting fact in this list is also the variety in sizes of the Tortoises who have lived the longest which all the more fortifies the fact that they were exceptions. It is common knowledge that bigger the species in size, longer the expected lifespan. But, species of smaller sizes have also live phenomenally long.

 

[Tom]

No one knows the answer to this question. No one living today will ever know the answer to this question. Too many variables and too many years to keep accurate, verifiable records. Further, we've only just begun breeding them and gaining a basic understanding of how to raise some species in the last couple of decades. Without knowing the hatch date and the details of how each baby was started, it will be difficult to pin down an age. Orv's example illustrates this. He mentions the tortoise was at least 20 years old. How do we know that? Did it live with someone else for 20 years? Are we guessing that age by size, weathering, appearance, or some other factor? So many animals were wild caught imports that it will be a while before we figure out what the "average" age of any given species could potentially be, if they are fed, housed, and cared for correctly.

I know of a recorded box turtle that lived 182 years. I read an article that speculated: Turtles and tortoises live until something kills them. The telomeres that begin to unravel with age on most living species of animals, which id what makes a 90 year old man or woman look different then a 20 year old, do not begin to unravel on adult tortoises. The aforementioned box turtle died when it escaped the family yard and was hit by a car. It was healthy, eating and behaving normally prior to that.

 

[niraj]

No one knows the answer to this question. No one living today will ever know the answer to this question. Too many variables and too many years to keep accurate, verifiable records. Further, we've only just begun breeding them and gaining a basic understanding of how to raise some species in the last couple of decades. Without knowing the hatch date and the details of how each baby was started, it will be difficult to pin down an age. Orv's example illustrates this. He mentions the tortoise was at least 20 years old. How do we know that? Did it live with someone else for 20 years? Are we guessing that age by size, weathering, appearance, or some other factor? So many animals were wild caught imports that it will be a while before we figure out what the "average" age of any given species could potentially be, if they are fed, housed, and cared for correctly.

I know of a recorded box turtle that lived 182 years. I read an article that speculated: Turtles and tortoises live until something kills them. The telomeres that begin to unravel with age on most living species of animals, which id what makes a 90 year old man or woman look different then a 20 year old, do not begin to unravel on adult tortoises. The aforementioned box turtle died when it escaped the family yard and was hit by a car. It was healthy, eating and behaving normally prior to that.

Thank you for your response. I think a study of records maintained by the zoos all over the world can be an authentic source of information. Many zoos have been in existence now for centuries. In fact, Alipore zoo, Kolkata in my country - India was home to Adwaita - the longest living giant aldabra tortoise who came to the zoo in 1875 and passed away in 2006.

By the way, can you kindly share the link of the article on the 184 years old box turtle?

 

[Markw84]

A consideration in talking "average" is that is really needs to be assessed with conditions - for example, the average lifespan of tortoises "that sucessfully reach breeding age", or "make it their first 20 years", etc.

If you look at wild populations of an animal like chelonians, the vast majority of hatchlings do no make it their first year. Something to the order of only 1 out of a few hundred with sulcatas, for example. For a population to be stable, an adult pair of sulcatas need to replace themselves with two more adult sulcatas before they die. If more than that make it to adulthood - the population is growing. If less than that make it - the population is shrinking. Since an adult female can easily produce 50 or more eggs per year, in 20 productive years, she has produced 1000 eggs. If 2 of those make it to become breeding adults, the population is stable and the species is "successful". However, in this example, the "AVERAGE" lifespan of the tortoises would be somewhere in the range of less than 1 year.

As @Tom points out above, it is more accurate to say a tortoise lives until something kills it. Average life "expectancy" is almost meaningless. It is only when we start keeping tortoises ( and koi, and parrots, etc, etc) in captive, protected environments, and begin to understand the true optimal requirements of these animals, that the life expectancy POTENTIAL of these animals becomes a consideration. But in captivity, that vast majority of the animals are still at risk of poor management, accident, and certainly disease and diseases exposed to in environment they would never experience in their "natural" environment. So even in captivity, almost all tortoises live until something kills it. That makes, again, the use of "average" of little value. The average age of a tortoise in Tom's care, for example, would be vastly different than the average age of a tortoise sold in the average pet shop.

Just as with humans, life expectancy of tortoises are improving and increasing with better knowledge and medicine, understanding of diet, nutrition, etc, etc. We are to this day still pushing up the average life expectancy of humans on a yearly basis. We have just begun to scratch the surface of that subject with tortoises.

That is where looking at the examples, where we can find them, of the longest attained lifespan so far - will at least give us an idea of the lifespan "potential of tortoises. Attaining that is more up to us, and our care for them, than it is to the tortoise.

 

[Yvonne G]

I read a paper long ago that said tortoises don't age. If accidents or illness didn't intervene tortoises may live forever. And a female tortoise's reproduction parts are just as good at 80 years of age as they were at 10 years of age.

The way a tortoise is cared for in captivity makes a big difference in how long it's going to live.

 

[wccmog10]

This is an interesting question and if anyone can somehow figure out what the answer is- that will be amazing. I agree with several of the comments that have been made. Zoos can be a great source of data for the longevity of some of these tortoise species, but you also have to remember that lots of their older animals are wild caught as well. I know of several galaps, Aldabras, radiateds, and box turtles that came to zoos in the 50s and 60s (some earlier) as wild caught individuals of unknown age. You have to remember that times were different then. Captive breeding was not what it is today. When you go back far enough zoos mentalities were not conservation- if an animal passed away they would retrieve another one from the wild. Only recent history (say the past 50-75 years) has the mentality changed to what we perceive today. Now in saying that- I feel that this "black cloud" time in the history of zoos is when we started the process of figuring out captive breeding and what conservation was. Anytime you start something new there will be learning curves. With that being said- my point about the zoo animals is that an individual animal at at zoo in 1875 was most likely not receiving the care that could be provided in todays world, not to mention it was wild caught and probably of unknown age. We knew so little about husbandry ~150 years ago. Not only was husbandry different, but I can't imagine that there are to many notes about what was being done- I can only imagine that record keeping was very sparse. Today zoos document everything. I used to spend lots of time at the end of my day documenting what I had done- which enclosures I cared for, if I provided any enrichment, if I moved an animal from one area to another, if I put animals together for breeding, etc. We could however use these wild caught individuals to start establishing minimum ages, ex. Adwaita was a minimum of 136 years old- but there is no way to confirm a number any larger than that (at least no way that I know of currently, however I heard of some methods using bones). Then there is the part about how many of the turtles are in zoos. When you think about it- zoos do not have anywhere near the number of animals as you would find in the wild. There are 232 accredited zoos and aquariums in North America currently- and they do not all have tortoises. I don't feel like zoos would ever be able to house enough individuals of a single species in order for us to make inferences about how long the "average" life span is of that species. But using zoo records to document how long a single individual of that species CAN live is a very real possibility. I feel like as we move forward with our husbandry knowledge this number (for some species such as tortoises) will get larger and larger. But it will take very long time before we have this information- 200+ years is a long time to wait to get the answer to a question, and the only individuals that will be usable to answer the question are ones that were born in captivity and received proper care.

Then there is also the part about captivity vs the wild. For some spices, such as Komodo dragons, we believe they live shorter lives in captivity than in the wild. Other species, such as eagles, live longer lives in captivity than the wild. There are plenty of other examples, these are just two that come to mind. It just depends what question you are asking. How long this species CAN live, how long is average, how long is average in captivity vs the wild, etc.?

-Wade

PS- I do have the answer to one of the questions- The average lifespan of a turtle in the wild is 0- since most of the eggs never even hatch and a lot of the eggs that do hatch, the neonates get eaten at a very small size. Now if you eliminate the individuals that die extremely young and only look at individuals that survive the high mortality stages and reach adulthood (which I think is realistic question to ask) I don't know what your answer is.

 

[no one]

I was just thinking about this last week. I read an Elongata doesn't live as long as a Star Tortoise could. But mine both in Captivity have much better circumstances then their species in the wild. I carefully follow the care listed on this forum. So hopefully I change the lifespan of my Elongata, Turt. So Turt and Indu can both be with when I am really old.

 

[niraj]

This is an interesting question and if anyone can somehow figure out what the answer is- that will be amazing. I agree with several of the comments that have been made. Zoos can be a great source of data for the longevity of some of these tortoise species, but you also have to remember that lots of their older animals are wild caught as well. I know of several galaps, Aldabras, radiateds, and box turtles that came to zoos in the 50s and 60s (some earlier) as wild caught individuals of unknown age. You have to remember that times were different then. Captive breeding was not what it is today. When you go back far enough zoos mentalities were not conservation- if an animal passed away they would retrieve another one from the wild. Only recent history (say the past 50-75 years) has the mentality changed to what we perceive today. Now in saying that- I feel that this "black cloud" time in the history of zoos is when we started the process of figuring out captive breeding and what conservation was. Anytime you start something new there will be learning curves. With that being said- my point about the zoo animals is that an individual animal at at zoo in 1875 was most likely not receiving the care that could be provided in todays world, not to mention it was wild caught and probably of unknown age. We knew so little about husbandry ~150 years ago. Not only was husbandry different, but I can't imagine that there are to many notes about what was being done- I can only imagine that record keeping was very sparse. Today zoos document everything. I used to spend lots of time at the end of my day documenting what I had done- which enclosures I cared for, if I provided any enrichment, if I moved an animal from one area to another, if I put animals together for breeding, etc. We could however use these wild caught individuals to start establishing minimum ages, ex. Adwaita was a minimum of 136 years old- but there is no way to confirm a number any larger than that (at least no way that I know of currently, however I heard of some methods using bones). Then there is the part about how many of the turtles are in zoos. When you think about it- zoos do not have anywhere near the number of animals as you would find in the wild. There are 232 accredited zoos and aquariums in North America currently- and they do not all have tortoises. I don't feel like zoos would ever be able to house enough individuals of a single species in order for us to make inferences about how long the "average" life span is of that species. But using zoo records to document how long a single individual of that species CAN live is a very real possibility. I feel like as we move forward with our husbandry knowledge this number (for some species such as tortoises) will get larger and larger. But it will take very long time before we have this information- 200+ years is a long time to wait to get the answer to a question, and the only individuals that will be usable to answer the question are ones that were born in captivity and received proper care.

Then there is also the part about captivity vs the wild. For some spices, such as Komodo dragons, we believe they live shorter lives in captivity than in the wild. Other species, such as eagles, live longer lives in captivity than the wild. There are plenty of other examples, these are just two that come to mind. It just depends what question you are asking. How long this species CAN live, how long is average, how long is average in captivity vs the wild, etc.?

-Wade

PS- I do have the answer to one of the questions- The average lifespan of a turtle in the wild is 0- since most of the eggs never even hatch and a lot of the eggs that do hatch, the neonates get eaten at a very small size. Now if you eliminate the individuals that die extremely young and only look at individuals that survive the high mortality stages and reach adulthood (which I think is realistic question to ask) I don't know what your answer is.

Thank you for t9ur

A consideration in talking "average" is that is really needs to be assessed with conditions - for example, the average lifespan of tortoises "that sucessfully reach breeding age", or "make it their first 20 years", etc.

If you look at wild populations of an animal like chelonians, the vast majority of hatchlings do no make it their first year. Something to the order of only 1 out of a few hundred with sulcatas, for example. For a population to be stable, an adult pair of sulcatas need to replace themselves with two more adult sulcatas before they die. If more than that make it to adulthood - the population is growing. If less than that make it - the population is shrinking. Since an adult female can easily produce 50 or more eggs per year, in 20 productive years, she has produced 1000 eggs. If 2 of those make it to become breeding adults, the population is stable and the species is "successful". However, in this example, the "AVERAGE" lifespan of the tortoises would be somewhere in the range of less than 1 year.

As @Tom points out above, it is more accurate to say a tortoise lives until something kills it. Average life "expectancy" is almost meaningless. It is only when we start keeping tortoises ( and koi, and parrots, etc, etc) in captive, protected environments, and begin to understand the true optimal requirements of these animals, that the life expectancy POTENTIAL of these animals becomes a consideration. But in captivity, that vast majority of the animals are still at risk of poor management, accident, and certainly disease and diseases exposed to in environment they would never experience in their "natural" environment. So even in captivity, almost all tortoises live until something kills it. That makes, again, the use of "average" of little value. The average age of a tortoise in Tom's care, for example, would be vastly different than the average age of a tortoise sold in the average pet shop.

Just as with humans, life expectancy of tortoises are improving and increasing with better knowledge and medicine, understanding of diet, nutrition, etc, etc. We are to this day still pushing up the average life expectancy of humans on a yearly basis. We have just begun to scratch the surface of that subject with tortoises.

That is where looking at the examples, where we can find them, of the longest attained lifespan so far - will at least give us an idea of the lifespan "potential of tortoises. Attaining that is more up to us, and our care for them, than it is to the tortoise.

Thank you for your elaborate response . I would say, in order to determine an average life expectancy , examples of tortoises having lived passed an year can be considered, more particularly larger species where it takes about an year for the shell to develope. In the link posted by me in my earlier message above, the researchers have taken a similar approach by finding a median of birds who have reached an age of four years to eliminate juvenile mortality.

 

[niraj]

A very interesting compilation of reptile lifespans is available here - http://pondturtle.com/lturtle.html