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when to take deciding weight
Posted: 06/09/2009 by Ozric

Hi!  Last year I pulled out of hibernating one of my tortoises at the last minute and decided to get that one going again and kept her up all winter.  The reason I did this was that her weight went below the safe line on the Jackson Ration when the wind-down period was almost up.  Her weight had been fine when wind-down started but she lost too much during wind down.

Interestingly this tortoise gained hardly any weight over the winter despite being kept up with heat and light and fed.

So my question is partly about when to take this 'deciding weight' measurement, is it before starting wind down or at the end of it?  I think connected to this is the temperature the tortoise is maintained at during wind-down.  Maybe it was too warm and she was hungry and used too much reserves up. I'm interested in either having a shorter wind-down for that tortoise or having one where the temperature goes down sooner to avoid the animal being so stimulated by light and heat and loosing too much weight. 

Thanks for any suggestions. 

Re: when to take deciding weight
Posted: 08/09/2009 by Shelbyville

Last year I took the pre wind down weight and worked out 10% weight loss from that. Both my horsfields had lost 10% of their body weight by the end of wind down and as they were only six months old at the time I didn't hibernate. But at the time I could not get a difinative answer about the weight loss that occurs in wind down and whether it needs to be counted in the total for the 10% weight loss rule.

Good Luck


Re: when to take deciding weight
Posted: 11/09/2009 by Ozric

Thanks for that Rachel!  Strange shortage of replies to this question which I asked last year as well - maybe thats why! Oz

Re: when to take deciding weight
Posted: 15/09/2009 by TPGDarren


There is no exact science when it comes to wind-down, hibernation, weight loss etc as there are so many other contributing factors. The Jackson ratio is only a guideline as are all hibernation guidelines. The length measurement (SCL) is not 100% in determining what weight a tortoise should be prior to hibernation. A tortoise with larger flaring will of course have an acceptable lesser weight than a tortoise with less flaring. A higher domed tortoise should weigh more prior to hibernation than a less domed tortoise. The Jackson ratio does not make allowances for any of these factors as well as many others, but is still the best guideline around today for Spurs & Hermanns. We have an adult tortoise here that is flat and has always been border-line on the Jackson ratio, yet has successfully hibernated every year. We tend to keep a record of their pre-hibernation weights each year, monitor their activity and run a health check on them prior to hibernation and have upper and lower hibernation weight for all our adults.

With young juvenile tortoises itís obviously more complicated as there are no records and of course their weight will change each year due to growth. Itís not advisable to feed them too much through the year in preparation for hibernation as it will have an adverse affect on steady growth and will actually be detrimental to the hibernation process. Weíve often made the decision to wind-down a tortoise for hibernation based on a juvenileís activity, growth & general state of health. Slow steady weight gain throughout the summer is a good indication a juvenile tortoise is healthy.

Sorry this hasnít been answered earlier, it is impossible to provide an absolute failsafe blueprint for hibernation/wind-down. As long as a tortoise is healthy, has had sufficient heat to consume and digest food during the summer months, has gained weight steadily (for juveniles), is provided with a good environment to hibernate in and doesnít lose a drastic amount of weight during wind-down Ė we always hibernate our tortoises.
Knowing your tortoise is without a doubt one of the most crucial parts of the hibernation process.

I remember us having a debate about this last year which lasted a good few days. Would you mind reminding us of the measurements you took; SCL, weight before and after wind-down please? I seem to recollect the weight-loss was relatively high in comparison to your tortoiseís body-weight?
Iíll have a look and see if I can find some wind-down info on the juveniles I have hibernated in the past here.

It would be interesting to create a database where people could add the details of length, wind-down period, pre wind-down and post wind-down weights and could easily set one up on our other forum.


Re: when to take deciding weight
Posted: 26/09/2009 by Ozric

Darren thanks for that reply - very useful.  Although I took lots of measurements and weights I seem not to have kept all the details. 

I've looked back at what details I did keep. The tortoise that I pulled out of hibernating peaked at 110 grammes in August last year and was 80mm.  She was 5 years old that month.  What's noticeable is that she was already down to 90grammes before I stopped offering food which was in November.  She had definitely been eating between August and November and was indoors under lamps after a date in early October and was fed every day until I started wind-down. Maybe I should not have even started a wind-down for that tortoise as it had lost quite a bit of weight already.  After about two weeks of wind-down she had lost a few grammes more and when I checked the JR she was below the line then (I used the calculation that gives a number not the graph).

Maybe I have answered my own question to an extent, because if I had been winding this tortoise down from her peak she would have been fine to hibernate.  But for some reason she lost quite a lot of weight before I stopped offering food and on reflection that should have told me something wasn't right. 

That tortoise has eaten well this summer and gained weight but I don't have all the measurements to hand.  I'll keep a weekly check on weight to see if it drops.  If her weight starts falling even though she's eating and indoors now, I might consider doing a wind-down sooner that I am planning at the moment.

This year one of my two year-olds has been quite inactive and hardly eating even though the conditions are the same as for the others who are all very active and eating strongly.  That little one seems to have decided to start her own wind-down and my placing her near the heat and light isn't working because after a short time she goes off to her hiding place and has a rest there. I'm going to measure and weigh that tortoise tomorrow and perhaps start a wind-down for that one as its a very long way to spring from here and I just cannot imagine that one keeping going till December when I was planning to hibernate.


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