Hibernation... again

[Pussygalore]

I am refering to torts that spend the summer outside not those that live inside but to be honest as all of mine have always been outside in the summer, which I think is best, I've never experienced one that only lives inside. Also mine are adult and have hibernated all their lives with their owners before me, and my female was orriginally wild caught, if you don't ever hibernate from the start then I assume it would be easier to keep them awake. However there is also the question of space my adult Ibera are fairly big and having only know the outside space hate being restricted even for the few days either side of hibernation, my male paces all day and the female hides away, this is the behaviour I get from an animal used to freedom. Its not very nice to see and not something I'd want to persist with to see how long it would last, they are telling me they are unhappy and my animals mental state is as important as their health. They have heat and combined bulbs in their outdoor houses but that doesn't prevent them from stopping eating around the middle/end of sept despite the weather still being sunny or hot, they will still come out, wander etc but won't eat anything not even treats such as cucumber, eventually the comming out becomes shorter untill they don't appear at all and that is still with the lights/heat on. They stop basking under the light and stay buried in their bedding and even if the house is in the high 80's they will feel cold to touch. This though is the behaviour of an adult tort that has always been hibernated and I feel it would be detrimental to their well being to try and change them even if I could. Just to add I still had hatchlings untill the begin of this year and as they'd not been outside and were in under lights etc had no problems in keeping them alert and eating, however whether that changes as they get older I wouldn't know as I've never tried it before, but certainly at some point size would be an issue unless you're happy keeping an animal in a small space and it hasn't know big enclosures outside. I'd not even consider keeping either of my adults in a table as even the biggest wouldn't be big enough .

[Petrus]

Originally Posted by Pussygalore

I am refering to torts that spend the summer outside not those that live inside but to be honest as all of mine have always been outside in the summer, which I think is best, I've never experienced one that only lives inside. Also mine are adult and have hibernated all their lives with their owners before me, and my female was orriginally wild caught, if you don't ever hibernate from the start then I assume it would be easier to keep them awake. However there is also the question of space my adult Ibera are fairly big and having only know the outside space hate being restricted even for the few days either side of hibernation, my male paces all day and the female hides away, this is the behaviour I get from an animal used to freedom. Its not very nice to see and not something I'd want to persist with to see how long it would last, they are telling me they are unhappy and my animals mental state is as important as their health. They have heat and combined bulbs in their outdoor houses but that doesn't prevent them from stopping eating around the middle/end of sept despite the weather still being sunny or hot, they will still come out, wander etc but won't eat anything not even treats such as cucumber, eventually the comming out becomes shorter untill they don't appear at all and that is still with the lights/heat on. They stop basking under the light and stay buried in their bedding and even if the house is in the high 80's they will feel cold to touch. This though is the behaviour of an adult tort that has always been hibernated and I feel it would be detrimental to their well being to try and change them even if I could. Just to add I still had hatchlings untill the begin of this year and as they'd not been outside and were in under lights etc had no problems in keeping them alert and eating, however whether that changes as they get older I wouldn't know as I've never tried it before, but certainly at some point size would be an issue unless you're happy keeping an animal in a small space and it hasn't know big enclosures outside. I'd not even consider keeping either of my adults in a table as even the biggest wouldn't be big enough .

I think you have raised an important point. It comes down to what an animal is USED to, not what an animal actually needs. Yours have always been kept outside in the summer and brought inside and hibernated in the winter. Surely the sudden change of having an animal outside and then bringing it inside is a huge change for a tortoise and this change would be part of the problem with not eating etc. As Ed said, animals in the southern areas, where the temperatures are good all year round, don't hibernate. Therefore the conclusion is the same, tortoises only hibernate to stay alive when the climate is unsuitable. If the conditions are correct then there is no need for hibernation

[Kirkie]

Originally Posted by Anita Sayles

So why do many experienced keepers choose to keep their animals 'ticking over' during winter?
What are the benefits?

What lead keepers to the train of thought that tortoises need brumation/hibernation in captivity when we can provide heat/light and food through the winter months keeping them active and well.

Another good question. I don't rate myself as a keeper of any great experience and I can't speak for anyone else but I'm fasinated by the concept that they can actually do this.

Lets start with " my tortoise knows when to prepare for hibernation".

Everything I've read on the subject suggests to me that prehibernation behaviour is determined by external factors. Mainly temperature, which stimulates certain cellular level hormonal changes to occur. Not just low temperatures, some are cued by the high season peak and the descent in temperature begins the cellular reconfiguration into hibernation mode.
Whilst temperature is the main factor I feel that secondary signals such as day length, light intensity, perhaps UV concentration in sunlight and perhaps baromic pressure play a role. I dont need to point to the hundreds of late season and overwintering behaviour posts to explain why I think this is the case. In my mind as soon as the temperature drops from its July/August peak, things are happening in a tortoises body to prepare it for hibernation. I dont fully understand the implications of supressing this, it has a lot to do with oxygen consumption and the conversion and storage of lipids and simple carbohydrates, the hibernation and post hibernation fuel.

Post hibernation tortoises are full of life, refreshed.*

Difficult to evaluate, the last time an owner saw the tortoide was during the wind down when it would have been lethargic. However, a post hibernation tortoises system is flooded with glycogen, a simple carbohydrate. Its a mechanism to boost the tortoise out of it torpor and to begin normal activities. Perhaps this perceived hyperactivity is a "sugar rush"?*

Increased breeding activity and fertility.

Post hibernation mating behaviour is well documented. It corresponds with the time of year this activity would mainly take place in the wild. The timing makes sense, the eggs will spend the hottest part of the year in the warmest ground, hatchlings emerging as the real heat is off and there is once again abundent food available.
Late season mating is also observed and there is evidence that a sucessful mating at this time results in rfertile eggs the following spring.
The production of sperm by a male Hermanms tortoise begins at 26C and ceases at 21C. There appears to be a lack of correlation between the sperm production cycle of wild and captive T Hermanni. However, I've seen it stated several times that hibernation increases the sperm count of male tortoises "by 25%". *There is evidence of increased testosterone levels in emerging males:

http://www.sciencedirect.com/science...d&searchtype=a

I don't know if this has been tested in emerging and non hibernated captive tortoises. Male behaviour I have personally witnessed would indicate an increased testosterone level at this time.

Feeding

Tortoises don't hibernate due to a lack of food. If it was warm enough a tortoise could sustain itself for long periods without eating. Summer estivation is a case in point. It is temperature, not food availability, that is the basis of this behaviour.

My personal choice is to attempt to replicate the annual feeding cycle of a Hermanns tortoise as closely as possible in terms of availability, nutritional value etc. I admit to having a shotgun approach to plants. Whilst its recorded that Hermanns tortoises don't eat the hundreds of wild plants available to them, in fact they are selective and have favourites amongst their selections, I go for a more holistic approach, feeding about 70 plant species to my tortoises. My bookshelf is a 50/50 split of tortoise/Med plant books. I feed things that would make most tortoise keeper faint but its the variety and balance that works. I can't do this in the winter. I can grow plants right the way through, indeed I do so I have some food ready for the spring but inkeeping with my personal ideology of replicating annual feeding cycles, there is a chunk of the year a Hermanns does not feed at all, the winter. So from a provision of food point of view, hibernation makes sense to me.

Hibernation puts huge pressures on the animal. You are essentially exposing it to a period where it cannot defend itself physically or*haematologically. I understand the lifecycle of a tortoise white blood cell is 8 weeks, production of new white blood cells is negligable during hibernation. At very low temperatures a chelonian body switches from using lipids (fats) to simple carbohydrates for the energy required to keep the metabolism ticking over. This is in limited supply and is totally dependent on the tortoise having been able to fabricate and store enough during the proceeding season.*

Tortoise hibernation is probably not as long as you think. *November to late February, eary March is typical for a Hermanns tortoise. Once hibernation is broken there may be a period of partial activity (mainly basking) where conditions waver between favourable and unsuitable for the tortoise. The tortoises is probably dependent on stored reserves (and possibly some remnants from the gut) during this period, they are rarely seen to feed and the main aim appears to be the kickstarting of the metabolic process through heat exposure.
It was always written that a tortoise exiting hibernarion releases a store of glycogen into the bloodstream enabling it to get going again. This was also cited why a tortoise should never be allowed to reenter hibernation. I don't see it. Firstly, there are many reports of this exact behaviour in multiple species of Chelonia. Secondly, the chance that when the post hibernation glycogen levels were tested perhaps the tortoises system is in glycogen production overdrive, that its not necessarily a release of a store but active production. Thats a personal view.

Theres a few pros and cons there. I haven't really touched on what I percieve as the cons of overwintering for your average keeper. I need to have a think about that because its not something I've given a lot of thought too!

[Pussygalore]

Peter you to have a point, I also think you have to take into account the animal ! if you have a hatchling and don't hibernate then you may never have the 'want to hibernate' behaviour however if you read the posts then sometimes even those who have torts that have never hibernated can still get the not eating, sleeping etc even with full lights and heat and you can't always put it down to illness or worms. I don't think you can say I'll never hibernate as some of it will depend on the animal as it gets older and how hard you wish to push the matter.

[Petrus]

Originally Posted by Kirkie

Another good question. I don't rate myself as a keeper of any great experience and I can't speak for anyone else but I'm fasinated by the concept that they can actually do this.

Lets start with " my tortoise knows when to prepare for hibernation".

Everything I've read on the subject suggests to me that prehibernation behaviour is determined by external factors. Mainly temperature, which stimulates certain cellular level hormonal changes to occur. Not just low temperatures, some are cued by the high season peak and the descent in temperature begins the cellular reconfiguration into hibernation mode.
Whilst temperature is the main factor I feel that secondary signals such as day length, light intensity, perhaps UV concentration in sunlight and perhaps baromic pressure play a role. I dont need to point to the hundreds of late season and overwintering behaviour posts to explain why I think this is the case. In my mind as soon as the temperature drops from its July/August peak, things are happening in a tortoises body to prepare it for hibernation. I dont fully understand the implications of supressing this, it has a lot to do with oxygen consumption and the conversion and storage of lipids and simple carbohydrates, the hibernation and post hibernation fuel.

Post hibernation tortoises are full of life, refreshed.*

Difficult to evaluate, the last time an owner saw the tortoide was during the wind down when it would have been lethargic. However, a post hibernation tortoises system is flooded with glycogen, a simple carbohydrate. Its a mechanism to boost the tortoise out of it torpor and to begin normal activities. Perhaps this perceived hyperactivity is a "sugar rush"?*

Increased breeding activity and fertility.

Post hibernation mating behaviour is well documented. It corresponds with the time of year this activity would mainly take place in the wild. The timing makes sense, the eggs will spend the hottest part of the year in the warmest ground, hatchlings emerging as the real heat is off and there is once again abundent food available.
Late season mating is also observed and there is evidence that a sucessful mating at this time results in rfertile eggs the following spring.
The production of sperm by a male Hermanms tortoise begins at 26C and ceases at 21C. There appears to be a lack of correlation between the sperm production cycle of wild and captive T Hermanni. However, I've seen it stated several times that hibernation increases the sperm count of male tortoises "by 25%". *There is evidence of increased testosterone levels in emerging males:

http://www.sciencedirect.com/science...d&searchtype=a

I don't know if this has been tested in emerging and non hibernated captive tortoises. Male behaviour I have personally witnessed would indicate an increased testosterone level at this time.

Feeding

Tortoises don't hibernate due to a lack of food. If it was warm enough a tortoise could sustain itself for long periods without eating. Summer estivation is a case in point. It is temperature, not food availability, that is the basis of this behaviour.

My personal choice is to attempt to replicate the annual feeding cycle of a Hermanns tortoise as closely as possible in terms of availability, nutritional value etc. I admit to having a shotgun approach to plants. Whilst its recorded that Hermanns tortoises don't eat the hundreds of wild plants available to them, in fact they are selective and have favourites amongst their selections, I go for a more holistic approach, feeding about 70 plant species to my tortoises. My bookshelf is a 50/50 split of tortoise/Med plant books. I feed things that would make most tortoise keeper faint but its the variety and balance that works. I can't do this in the winter. I can grow plants right the way through, indeed I do so I have some food ready for the spring but inkeeping with my personal ideology of replicating annual feeding cycles, there is a chunk of the year a Hermanns does not feed at all, the winter. So from a provision of food point of view, hibernation makes sense to me.

Hibernation puts huge pressures on the animal. You are essentially exposing it to a period where it cannot defend itself physically or*haematologically. I understand the lifecycle of a tortoise white blood cell is 8 weeks, production of new white blood cells is negligable during hibernation. At very low temperatures a chelonian body switches from using lipids (fats) to simple carbohydrates for the energy required to keep the metabolism ticking over. This is in limited supply and is totally dependent on the tortoise having been able to fabricate and store enough during the proceeding season.*

Tortoise hibernation is probably not as long as you think. *November to late February, eary March is typical for a Hermanns tortoise. Once hibernation is broken there may be a period of partial activity (mainly basking) where conditions waver between favourable and unsuitable for the tortoise. The tortoises is probably dependent on stored reserves (and possibly some remnants from the gut) during this period, they are rarely seen to feed and the main aim appears to be the kickstarting of the metabolic process through heat exposure.
It was always written that a tortoise exiting hibernarion releases a store of glycogen into the bloodstream enabling it to get going again. This was also cited why a tortoise should never be allowed to reenter hibernation. I don't see it. Firstly, there are many reports of this exact behaviour in multiple species of Chelonia. Secondly, the chance that when the post hibernation glycogen levels were tested perhaps the tortoises system is in glycogen production overdrive, that its not necessarily a release of a store but active production. Thats a personal view.

Theres a few pros and cons there. I haven't really touched on what I percieve as the cons of overwintering for your average keeper. I need to have a think about that because its not something I've given a lot of thought too!

Outstanding post. I agree with much of what you say. A lot of common sense is applied here which is often lost admist the desire to be academic!

[Kirkie]

Originally Posted by Petrus

I think you have raised an important point. It comes down to what an animal is USED to, not what an animal actually needs. Yours have always been kept outside in the summer and brought inside and hibernated in the winter. Surely the sudden change of having an animal outside and then bringing it inside is a huge change for a tortoise and this change would be part of the problem with not eating etc. As Ed said, animals in the southern areas, where the temperatures are good all year round, don't hibernate. Therefore the conclusion is the same, tortoises only hibernate to stay alive when the climate is unsuitable. If the conditions are correct then there is no need for hibernation

I think what Ed said was that they are active when conditions are favourable. Bottom line is it's a percentages game for tortoises. They're hypersensitive to climactic conditions. A huge percentage of their energy requirement comes from external heat. If the energy consumed seeking out heat outweighs the potential gain from thermoregulation, the tortoise will sit tight. Its not hibernating, its conserving.

[Kirkie]

Ok, some cons. I'm not using these as a pro hibernation but to round things out.

We've all probably seen the statistic:

"For every drop of 10°C the tortoise heart rate drops 50%"

So, if you are overwintering a tortoise, you need to ensure that you tick all the boxes to ensure constant, full activity.
If your tortoise doesn't feel that the conditions make it worth the effort to bask and instead it remains in its "cool" area, attempting to conserveenergy, the tortoises metabolism is operating at a rate far far in excess of my tortoises hibernating at 5C. My hibernating tortoise is geared up to cope with this, metabolic activity is minimal. The tortoise at 20C has a close to fully functioning metabolism yet this function is dependent on stored reserves, not heat from basking. I think this has to be absolutely avoided in the long term.

Which brings me to overwintering care pracises. If you are maintaining a tortoise at a suitable temperature, you have to feed it proportionally, otherwise, it's again using up reserves. I've seen people advise to cut back on the amounts during the winter but this makes no sense to me. You're just denying the tortoise what it needs whilst making it fully active.
So what do you feed a tortoise over winter? Salad,shop produce, pellets perhaps, whatever weeds are available.

You have a tortoise receiving optimal (possibly over optimal if there is such a thing) requirements for growth 12 months a year.
Now remembering that you will have to provide an indoor summerlike regime for the tortoise throughout it's life. This isn't too hard for a couple of small, young Med tortoises but there is a possibile issue with this regime and your need to maintain it annually. I don't like to use this tortoise as a "poster girl" too often but this is Honey, a Hermanns I rehomed last year.
She lived indoors, was never hibernated and was fed daily on shop produce and tortoise pellets. When she came to me she was 1.9KG, 23 CM's SCL. According to her A10 certificate, she's a 2003 hatchling, she's 8. She has a few health issues but is getting there. The bumpy assed tortoise in front of her is a 2006 hatchling I've had for three years.





I don't post these to say "this is what will happen". I'm sure people will give a little more thought to how they overwinter their tortoises.
I'm trying to show that you will have to provide optimal conditions for a tortoise like this through the winter for the rest of its life.

[Petrus]

Originally Posted by Kirkie

I think what Ed said was that they are active when conditions are favourable. Bottom line is it's a percentages game for tortoises. They're hypersensitive to climactic conditions. A huge percentage of their energy requirement comes from external heat. If the energy consumed seeking out heat outweighs the potential gain from thermoregulation, the tortoise will sit tight. Its not hibernating, its conserving.

That'sa what I'm saying, Kirkie. If the conditions are favourable then the tortoise doesn;t need to hibernate. It's a response to climatic change? Yes?

[Petrus]

Originally Posted by Kirkie

Ok, some cons. I'm not using these as a pro hibernation but to round things out.

We've all probably seen the statistic:

"For every drop of 10°C the tortoise heart rate drops 50%"

So, if you are overwintering a tortoise, you need to ensure that you tick all the boxes to ensure constant, full activity.
If your tortoise doesn't feel that the conditions make it worth the effort to bask and instead it remains in its "cool" area, attempting to conserveenergy, the tortoises metabolism is operating at a rate far far in excess of my tortoises hibernating at 5C. My hibernating tortoise is geared up to cope with this, metabolic activity is minimal. The tortoise at 20C has a close to fully functioning metabolism yet this function is dependent on stored reserves, not heat from basking. I think this has to be absolutely avoided in the long term.

Which brings me to overwintering care pracises. If you are maintaining a tortoise at a suitable temperature, you have to feed it proportionally, otherwise, it's again using up reserves. I've seen people advise to cut back on the amounts during the winter but this makes no sense to me. You're just denying the tortoise what it needs whilst making it fully active.
So what do you feed a tortoise over winter? Salad,shop produce, pellets perhaps, whatever weeds are available.

You have a tortoise receiving optimal (possibly over optimal if there is such a thing) requirements for growth 12 months a year.
Now remembering that you will have to provide an indoor summerlike regime for the tortoise throughout it's life. This isn't too hard for a couple of small, young Med tortoises but there is a possibile issue with this regime and your need to maintain it annually. I don't like to use this tortoise as a "poster girl" too often but this is Honey, a Hermanns I rehomed last year.
She lived indoors, was never hibernated and was fed daily on shop produce and tortoise pellets. When she came to me she was 1.9KG, 23 CM's SCL. According to her A10 certificate, she's a 2003 hatchling, she's 8. She has a few health issues but is getting there. The bumpy assed tortoise in front of her is a 2006 hatchling I've had for three years.





I don't post these to say "this is what will happen". I'm sure people will give a little more thought to how they overwinter their tortoises.
I'm trying to show that you will have to provide optimal conditions for a tortoise like this through the winter for the rest of its life.

So it the less bumpy tortoise the one that was kept indoors and never hibernated?

[Kirkie]

The bigger of the two is the tortoise in question. I wouldn't say shes free of carapace abnormalities if you loik at the dorsal scutes.

The smaller tortoise I've had for three seasons and has been hibernated each year with me. I dont know the previous routine with that one. The recent growth looks ok to me.