Telling the approximate age

[yuri2012]

Hi all. Ive heard many ways to try and determine the age of a tortoise. I have a russian male tortoise thats about 4 inches long from front of shell to the bottom of the shell. His name is Yuri. I was wondering how you folks determine age? Also if i were to post pics of him would it help with age telling?



Bonus question: Im using eco earth substrate and it's about 1 to 2 inches deep. Whats the preferred depth of the substrate since they like to dig and burrow?


Thanks in advance for any help.

 

[GeoTerraTestudo]

Scute rings give a rough indication of age up until about 20 years, but only for tortoises that live a wild or semi-wild existence, since their growth varies over the course of the year, creating rings.

Size is also a rough indicator of age, but it depends on how much the tortoise has been eating.

My Russians are also about 4 inches long SCL (straight carapace length). They are apparently WC (wild-caught), so I am not certain of their age. However, judging by the growth rings, I think they are about 5-7 years old.

Bonus answer: Russians are among the best burrowers in the turtle world, and like to dig. I also use 100% coco coir, but I give them 6 inches. They did regularly dig all the way down to the bottom back in November, as a preparation for hibernation. However, now in the growing season, the female digs down only a few inches, and the male has hardly dug down at all. Nevertheless, they have the option to completely cover themselves and more if they want to.

 

[dmarcus]

Hello and welcome to the forum...

I can't answer for russians but I know my box turtles can burrow pretty deep so I provide enough substrate so they can get down a couple inches if they choose to...

 

[ALDABRAMAN]

Welcome!

 

[yuri2012]

Thanks for the help guys. I really appreciate it.

 

[ascott]

Welcome to the Forum and we LOVE PICS

 

[Tom]

Hello and welcome. There is no reliable way to tell the age of a tortoise, unless you know the hatch date. There are just too many variables.

 

[GeoTerraTestudo]

Hello and welcome. There is no reliable way to tell the age of a tortoise, unless you know the hatch date. There are just too many variables.

Well, again, provided the tortoise lives under essentially natural conditions, eating more in the growing season, and eating less or becoming dormant in the winter, it is possible to use scute annuli (rings) to estimate, but only up to the age of about 15 reliably (Aresco and Guyer 1998, attached).

 

[Tom]

Hello and welcome. There is no reliable way to tell the age of a tortoise, unless you know the hatch date. There are just too many variables.

Well, again, provided the tortoise lives under essentially natural conditions, eating more in the growing season, and eating less or becoming dormant in the winter, it is possible to use scute annuli (rings) to estimate, but only up to the age of about 15 reliably (Aresco and Guyer 1998, attached).

I don't agree. They can get several growth rings in a good year or none at all in a bad year. I don't find it to be reliable. I find it to be a guess.

 

[Yvonne G]

I totally agree with Tom. I know for a fact that my Aldabrans are 12 years old. Yet if you count the growth rings, there are 18 of them.

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Hi Yuri2012:

Welcome to the Tortoise Forum!!

What would you like us to call you? ...and may we know appx. where in the world you are?

 

[Tom]

GTT, I know you are mainly talking about wild ones, BUT, many of the so-called "wild caught" ones that are imported here are "farm" raised over there, or in various parts of the world.

Even still, the weather where they come from can be so harsh and unpredictable, from what I have studied, that I really don't think I could count growth rings even on a true wild caught one, and feel confident that I was accurate on the age. I just think the count could be off be many years in either direction depending on the weather of the last 20 years and exactly where in the rather large range that particular wild one came from...

 

[Madkins007]

Scute rings are helpful in determining the relative age of one tortoise in a specific area or population compared to another one. Since they would all be adding rings at about the same rate, those with more would be older- so two 10" tortoises caught near each other. If one has 15 rings and the other has 20+ and worn, it is probably the older animal. Note, however, this does not mean that there is always one ring per year.

In some wild (and possibly even 'farmed in the native habitat') tortoises, they do indeed have such clear-cut growing seasons that the first many years of life produce predictable, clear rings. After that period, they get worn or crowded, etc. This is what the study referenced is referring to.

To use their research, you use the abdominal scute and count the 'real' rings, and ignore 'false' rings added due to inactivity, etc. rather than seasonal growth. False rings are identified as being smaller and shallower than growth rings.

This is almost certainly an effective method for the species that actually do have such clear seasons, as long as they are young enough to not wear old rings down. However, it really does not apply well to captive animals, etc.

For most of us, the best ways are still-
- knowing when it was born (100% reliable)
- using a growth chart (so-so, depending on the reliability of the data used)
- educated guessing based on experience, and
- wild guess based on size and limited experience

Since tortoises mature based more on size than age, age is not really as big a deal to them, so this is not that big a deal for most keepers other than sheer curiosity.

 

[yuri2012]

Yes. Yuri resides in Southeastern Pennsylvania, USA. We picked him up at a local Petco store. I measured him officially and hes about 10-11cm max so that's about 4 inches flat at best.

I've used to play with huge turtles when I was younger but I havn't had a turtle pet in over 12 years so I decided to begin again.

 

[GBtortoises]

Hello and welcome. There is no reliable way to tell the age of a tortoise, unless you know the hatch date. There are just too many variables.

Agreed. Growth rings on a tortoise (or turtle) are just that, growthrings. Not annual rings. Their growth is variable based on a multitude of favorable and unfavorable seasonal conditions.

 

[GeoTerraTestudo]

The authors of the article I attached above studied wild gopher tortoises, and counted rings on abdominal scutes. Up to the age of 15, they found a correlation between ring number and age of 0.98, which is very high, and a statistically significant slope. It seems that plastral scute rings are more reliable than carapacial ones.

BTW - On the carapace, I have found that there are two different types of rings: faint and bold. I think multiple faint lines can be added in a year, but bold ones demarcate one year from another. This is why, when I count rings, I try to skip the faint ones and note only the bold ones. I think this provides a better estimate of age than counting all the rings I see. Again, this would only work for temperate tortoises. Tropical ones may experience slower growth during the dry season, but not as slow as during winter in the north, where a tortoise may brumate altogether.

 

[GBtortoises]

So based on counting rings (lines) on abdominal scutes how old is the tortoise in the photo below (I already know how old he is)?
Assuming that there may be some accuracy in counting abdominal lines to determine age, if it is only accurate up to the age of 15 what value does that have with an animal that may well reach over 100 years old? So you may be able to determine it's age for the first 15% of it's total lifespan. Many species are barely sexually mature at that age in the wild. Again, all growth is determined by environmental conditions. I guess if you kept a tortoise under exact conditions for several years, never altering it's diet content & volume, water availability, temperatures, light duration & intensity as well as all other environmental factors, you could determine exactly how old it is by ring growth because you would know for certain that there were no environmental variables. The problem with this potential experiment is that young tortoises typically grow more rapidly their first 2-6 years and then slower as they reach maturity.
The faint and bold growth rings that you see on the carapace are exactly what takes place due to environmental variables.

 

[GeoTerraTestudo]

So based on counting rings (lines) on abdominal scutes how old is the tortoise in the photo below (I already know how old he is)?
Assuming that there may be some accuracy in counting abdominal lines to determine age, if it is only accurate up to the age of 15 what value does that have with an animal that may well reach over 100 years old? So you may be able to determine it's age for the first 15% of it's total lifespan. Many species are barely sexually mature at that age in the wild. Again, all growth is determined by environmental conditions. I guess if you kept a tortoise under exact conditions for several years, never altering it's diet content & volume, water availability, temperatures, light duration & intensity as well as all other environmental factors, you could determine exactly how old it is by ring growth because you would know for certain that there were no environmental variables. The problem with this potential experiment is that young tortoises typically grow more rapidly their first 2-6 years and then slower as they reach maturity.
The faint and bold growth rings that you see on the carapace are exactly what takes place due to environmental variables.

The method would be useless for tortoises older than 15 years of age, and I suspect it would be useless for tropical tortoises, too. However, it would be useful for temperate tortoises younger than age 15. Since the OP stated that his Russian tortoise is only about 4 inches long, odds are that it is quite a bit younger than 15, so this method would be probably useful in more closely pinpointing its exact age.

Again, this method is only useful with tortoises that live under wild or semi-wild conditions, in which they grow much faster in the summer than the winter, creating annuli. The natural variability in such systems does not appear to drown out ring formation. In other words, if you think in terms of signal-to-noise ratio, the noise of environmental variables does not exceed the signal of laying down abdominal scutes - but only in free-ranging tortoises under the age of about 15.

BTW - As for the tortoise in the above picture, assuming it is known to be less than 15, I would say it is about 6 years old. Am I right? I hope I am doing Aresco and Guyer's method justice.