Weight and brumation

[ursula]

Hi all,

my 9 hermannii and 3 greek tortoises have decided that it's time for them to get ready for brumation. They are slowing down, eating less, but still active during the day. Last year (their first winter in southeast Michigan), they had spent the summer in Italy and so they were nice and plump for brumation. This year, they spent their whole summer in Michigan, I fed them regularly and well (I hope!) and I just weighed them to see if they are ready for brumation. I also weighed them last March and in July just to make sure they were all gaining weight.

My tortoises are all adults, some much larger than others (their ages range from 60+ to 26 years). Here is a table with their weights (in grams):

	Sex	Species	3/15/2025​	7/6/2025​	9/28/2025​
Ermione	F	T.hermanni	1683​	1863​	1831​
Mirto	F	T.hermanni	958​	1005​	1020​
Piccola	F	T.hermanni	1201​	1241​	1229​
Viola	F	T.hermanni	1016​	1077​	1085​
Alain	M	T.hermanni	607​	688​	676​
Altair	M	T.hermanni	525​	550​	553​
Alkaid	M	T.hermanni	634​	696​	691​
Annibale	M	T.hermanni	660​	691​	684​
Flap	M	T.hermanni	458​	477​	453​
Blob	M	T.graeca	994​	1057​	1033​
Baal	M	T.graeca	1069​	1160​	1106​
Benjamin	M	T.graeca	1011​	1211​	1141​

As you can see, they are all heavier than back in March when I woke them up for brumation, which is good and expected. But quite a few are a little lighter than July. Is there a chart to estimate the weight they should be relative to their dimensions for a safe brumation? Other than weight, they all seem healthy with good breathing, bright eyes, and good activity levels.

Last year, I had them go into brumation at the beginning of November and woke them up beginning of March, as this was their usual schedule in Italy. This year I was thinking the same for November but, if necessary, I could wake them up earlier in February to make sure they have enough reserves.

Any thoughts?

Thanks!

 

[Littleredfootbigredheart]

lol @Tom is going to hate me cause I’m tagging him left right and centre todaybut he really is the best guy to comment here

 

[RandyTortoise]

Hi all,

my 9 hermannii and 3 greek tortoises have decided that it's time for them to get ready for brumation. They are slowing down, eating less, but still active during the day. Last year (their first winter in southeast Michigan), they had spent the summer in Italy and so they were nice and plump for brumation. This year, they spent their whole summer in Michigan, I fed them regularly and well (I hope!) and I just weighed them to see if they are ready for brumation. I also weighed them last March and in July just to make sure they were all gaining weight.

My tortoises are all adults, some much larger than others (their ages range from 60+ to 26 years). Here is a table with their weights (in grams):

	Sex	Species	3/15/2025​	7/6/2025​	9/28/2025​
Ermione	F	T.hermanni	1683​	1863​	1831​
Mirto	F	T.hermanni	958​	1005​	1020​
Piccola	F	T.hermanni	1201​	1241​	1229​
Viola	F	T.hermanni	1016​	1077​	1085​
Alain	M	T.hermanni	607​	688​	676​
Altair	M	T.hermanni	525​	550​	553​
Alkaid	M	T.hermanni	634​	696​	691​
Annibale	M	T.hermanni	660​	691​	684​
Flap	M	T.hermanni	458​	477​	453​
Blob	M	T.graeca	994​	1057​	1033​
Baal	M	T.graeca	1069​	1160​	1106​
Benjamin	M	T.graeca	1011​	1211​	1141​

As you can see, they are all heavier than back in March when I woke them up for brumation, which is good and expected. But quite a few are a little lighter than July. Is there a chart to estimate the weight they should be relative to their dimensions for a safe brumation? Other than weight, they all seem healthy with good breathing, bright eyes, and good activity levels.

Last year, I had them go into brumation at the beginning of November and woke them up beginning of March, as this was their usual schedule in Italy. This year I was thinking the same for November but, if necessary, I could wake them up earlier in February to make sure they have enough reserves.

Any thoughts?

Thanks!

I am unaware that anyone, in a disciplined manner, over many years of data put together something they you want. You do, however, have your collection of research subjects so you could easily collect that data with your own large collection!

As I understand, there is nothing harmful in waking them up early as you propose. That is probably a safe way to go about this for your first brumation and with such a large amount of tortoises. Better to be safe than sorry.

 

[ursula]

Hi all,

my 9 hermannii and 3 greek tortoises have decided that it's time for them to get ready for brumation. They are slowing down, eating less, but still active during the day. Last year (their first winter in southeast Michigan), they had spent the summer in Italy and so they were nice and plump for brumation. This year, they spent their whole summer in Michigan, I fed them regularly and well (I hope!) and I just weighed them to see if they are ready for brumation. I also weighed them last March and in July just to make sure they were all gaining weight.

My tortoises are all adults, some much larger than others (their ages range from 60+ to 26 years). Here is a table with their weights (in grams):

	Sex	Species	3/15/2025​	7/6/2025​	9/28/2025​
Ermione	F	T.hermanni	1683​	1863​	1831​
Mirto	F	T.hermanni	958​	1005​	1020​
Piccola	F	T.hermanni	1201​	1241​	1229​
Viola	F	T.hermanni	1016​	1077​	1085​
Alain	M	T.hermanni	607​	688​	676​
Altair	M	T.hermanni	525​	550​	553​
Alkaid	M	T.hermanni	634​	696​	691​
Annibale	M	T.hermanni	660​	691​	684​
Flap	M	T.hermanni	458​	477​	453​
Blob	M	T.graeca	994​	1057​	1033​
Baal	M	T.graeca	1069​	1160​	1106​
Benjamin	M	T.graeca	1011​	1211​	1141​

As you can see, they are all heavier than back in March when I woke them up for brumation, which is good and expected. But quite a few are a little lighter than July. Is there a chart to estimate the weight they should be relative to their dimensions for a safe brumation? Other than weight, they all seem healthy with good breathing, bright eyes, and good activity levels.

Last year, I had them go into brumation at the beginning of November and woke them up beginning of March, as this was their usual schedule in Italy. This year I was thinking the same for November but, if necessary, I could wake them up earlier in February to make sure they have enough reserves.

Any thoughts?

Thanks

and here is my little tortoise army

 

[Alex and the Redfoot]

Hi all,

my 9 hermannii and 3 greek tortoises have decided that it's time for them to get ready for brumation. They are slowing down, eating less, but still active during the day. Last year (their first winter in southeast Michigan), they had spent the summer in Italy and so they were nice and plump for brumation. This year, they spent their whole summer in Michigan, I fed them regularly and well (I hope!) and I just weighed them to see if they are ready for brumation. I also weighed them last March and in July just to make sure they were all gaining weight.

My tortoises are all adults, some much larger than others (their ages range from 60+ to 26 years). Here is a table with their weights (in grams):

	Sex	Species	3/15/2025​	7/6/2025​	9/28/2025​
Ermione	F	T.hermanni	1683​	1863​	1831​
Mirto	F	T.hermanni	958​	1005​	1020​
Piccola	F	T.hermanni	1201​	1241​	1229​
Viola	F	T.hermanni	1016​	1077​	1085​
Alain	M	T.hermanni	607​	688​	676​
Altair	M	T.hermanni	525​	550​	553​
Alkaid	M	T.hermanni	634​	696​	691​
Annibale	M	T.hermanni	660​	691​	684​
Flap	M	T.hermanni	458​	477​	453​
Blob	M	T.graeca	994​	1057​	1033​
Baal	M	T.graeca	1069​	1160​	1106​
Benjamin	M	T.graeca	1011​	1211​	1141​

As you can see, they are all heavier than back in March when I woke them up for brumation, which is good and expected. But quite a few are a little lighter than July. Is there a chart to estimate the weight they should be relative to their dimensions for a safe brumation? Other than weight, they all seem healthy with good breathing, bright eyes, and good activity levels.

Last year, I had them go into brumation at the beginning of November and woke them up beginning of March, as this was their usual schedule in Italy. This year I was thinking the same for November but, if necessary, I could wake them up earlier in February to make sure they have enough reserves.

Any thoughts?

Thanks!

Hello!
There are two "formulas" for assessing tortoise weight/size ratios: Donoghue ratio https://tortoiselibrary.com/health-and-medical-2/healthy-weight-and-size/ and Jackson ratio: https://www.tortoisetrust.org/articles/jackson.html

Besides the original papers, there were some consequent works on T. hermanni and T. graeca with larger samples and different ages and some proposed adjustments to the formulas.

However, these formulas are too generic and should be used with caution (it's better to have results calculated for each individual tortoise over time and set baselines individually).

Flap is the only "outlier" in the table (he is the smallest and his weight dropped since March). Maybe, I'll do a fecal test for this one. And if he is still in the mood to eat I would offer him food separately from the rest of the creep.

 

[mark1]

if they been eating and acting healthy , they're good......a turtle or tortoise at 32-50 degrees F, uses very little energy, i'd guess almost none ..... my box turtles, while i've never weighed one, will stop eating early october and will not eat again until mid to late may, and don't noticeably feel any lighter coming out of brumation as they did going into brumation, the water hibernators usually feel heavier............imo, they would need to be starving prior to brumation to have a problem....... a 3.6 kg gopher tortoise in july is said to use about 150 kJ/day of energy, .042kJ/g/day...... a ground squirrel weighing 100grams in april-may is said to use 134kJ/day energy, 1.34 kJ/g/day, i'm thinking that is like a 3000% difference in energy expenditure ....i think the energy requirements for a hibernating (32-50F) reptile are extremely over estimated.... my turtles hibernate outdoors, they are in and out of brumation throughout early and late winter, the water hibernators are in and out of brumation throughout winter , as are north american tortoises.... i've never seen one die from not eating, i've seen them not eat for as long as 8 months.......

 

[Yvonne G]

and here is my little tortoise army

Very impressive group of tortoises! Just out of curiosity, do you keep the Greeks separate from the Hermanni?

 

[ursula]

Very impressive group of tortoises! Just out of curiosity, do you keep the Greeks separate from the Hermanni?

no, they have been together for many years (40+). I know I run the risk of getting hybrids but these are tortoises that used to live mostly on their own in a yard before my family moved into that house in Italy many years ago. No point in separating them now. Plus, they do not really reproduce on their own, the warm climate is too short here in Michigan and in Italy the yard was too shaded so the eggs never hatched on their own.

 

[ursula]

if they been eating and acting healthy , they're good......a turtle or tortoise at 32-50 degrees F, uses very little energy, i'd guess almost none ..... my box turtles, while i've never weighed one, will stop eating early october and will not eat again until mid to late may, and don't noticeably feel any lighter coming out of brumation as they did going into brumation, the water hibernators usually feel heavier............imo, they would need to be starving prior to brumation to have a problem....... a 3.6 kg gopher tortoise in july is said to use about 150 kJ/day of energy, .042kJ/g/day...... a ground squirrel weighing 100grams in april-may is said to use 134kJ/day energy, 1.34 kJ/g/day, i'm thinking that is like a 3000% difference in energy expenditure ....i think the energy requirements for a hibernating (32-50F) reptile are extremely over estimated.... my turtles hibernate outdoors, they are in and out of brumation throughout early and late winter, the water hibernators are in and out of brumation throughout winter , as are north american tortoises.... i've never seen one die from not eating, i've seen them not eat for as long as 8 months.......

Thanks, I feel the same way for the most part but I do worry a little bit. When they were in Italy the brumation was completely natural, they lived in their habitat in a yard and were free to borrow and come out whenever they wanted. Now that they are in Michigan I am responsible for setting up the proper environment for them and I want to make sure I do it right.

I appreciate the information!

 

[ursula]

Hello!
There are two "formulas" for assessing tortoise weight/size ratios: Donoghue ratio https://tortoiselibrary.com/health-and-medical-2/healthy-weight-and-size/ and Jackson ratio: https://www.tortoisetrust.org/articles/jackson.html

Besides the original papers, there were some consequent works on T. hermanni and T. graeca with larger samples and different ages and some proposed adjustments to the formulas.

However, these formulas are too generic and should be used with caution (it's better to have results calculated for each individual tortoise over time and set baselines individually).

Flap is the only "outlier" in the table (he is the smallest and his weight dropped since March). Maybe, I'll do a fecal test for this one. And if he is still in the mood to eat I would offer him food separately from the rest of the creep.

Thank you, I'll definitely take a look. The fecal test for Flap is a good idea, I'll do that. Thanks!