Hibernation variant for temperate Testudo- safer even for beginners

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5 Year Member
Oct 13, 2011
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Bucharest, Romania z6
Some quotes and compilations of my messages on other forums that may help understand “hibernation/brumation/whatever-you-prefer-to-name-it”, below:

A method of somehow "interrupted brumation", kinda like a Mediteranean shore winter: imitate the alternating cold and warm days, hiding and emerging, cold (about 10*C in shade) days with sunshine resulting in really warm carapaces, enough to slowly keep digesting food etc.

It's way different from the "unproper lukewarm hibernation", although some may jump to conclude it's the same, since no true winter, nor true summer is maintained- wich is the worse situation for a tortoise. Yet, the good basking spot makes the difference; even not in daily use, it boost the tortoises systems for those few days on a row, while they eat, drink, defecate and keep their immune system "ON". While room temperatures may be only 10-15*C, through basking in a sheltered, warmer part of their enclosure, tortoise manage to reach active temperatures in their body.
That "warmer part" can be not just the place under the heating lamp, but, for instance, a polycarbonate large box with the heating lamps inside, to favour heat accumulation. That, together with the lamp radiation, will help the tortoise to get warmed more quickly. Of course, that small "greenhouse" should not be closed or ridiculously overheated, and the tortoise should be able to get in/out as she needs. Feeding place to be outside that "heat-trap", but in vicinity. Each keeper will design its overwintering quarters depending on his own conditions.

When no weeds available, for instance, just keep the light off for a few days- they will resume to sleep. It is over 13*C, so food will not rot in their stomachs- digestion is slowed, but not stopped. Then when food arrives, lights on, basking, stomping; bathing for flushing toxins, then feeding. I would call this "cool overwintering “.

In cold, true, uninterrupted hibernation, be it artificial or natural, the tortoises have no undigested food left in the stomach, but some harmless, relative dehydrated, totally digested meals, in the intestins. Those are subjected to the action of the specific, beneficial gut flora, not other germs, that may result in gases wich press the internal body cavity, causing bad function of the organs. The symbiotic bacteria "innoculi" are kept almost dried, conserved, in the guts, and, as quoted before, those faeces are totally digested and harmless, even beneficial. They maybe help to restore the full digestive flora faster than in indoor wind-down we practice, with frequent bathing, resulting in totally empty intestins.
Of course, better safe than sorry when artificially winding-down a tortoise for hibernation. Bathing is useful at least for expelling the bulk of urates, even it will flush too the last traces of totally digested, harmless rests of faeces.

Undigested food in the STOMACH- that's the problem. A tortoise that didn't went through a wind-down period (indoor, controled, or outdoor, spontaneously) and is put in hibernating conditions, should be in quite a dangerous situation, and I suspect the most of hibernation deaths are atributed to mistakes like that one. Mistakes and misinformation kill the tortoises, not hibernation.

... and a quote from other author, added by someone else:

"Originally Posted by Manuel Wegehaupt
However, reptiles are in general able to effect instinctive digging motions in response to changing environmental temperatures even while hibernating and so determine the depth at which they are buried. If the weather turns particularly cold, the tortoises will bury themselves to a depth where the frost cannot reach them. If, on the other hand, the weather turns warmer, they will respond with rising closer to or even above the surface. These default responses keep the tortoises alive in nature as they prevent both freezing to death and poisoning as a result of incomplete metabolic processes. Fluctuating air temperatures, on the other hand, do not affect the animals directly. Here, the soil works as a buffer that allows changes in temperature to be felt deep in the ground only if they persist for some time.

If continuous sunny weather keeps on warming the topsoil for some time, the tortoises may therefore appear on the surface and, attracted by the sunlight, expose themselves to the radiant warmth. To do so is of vital importance for the animals. In European tortoises, metabolic functions begin to set in slowly at a temperature of as low as 8C, even though it takes a body temperature of about 30C to run at full speed. Metabolic waste products are basically toxic, but can be stored away safely in the kidneys for some time. Persistent low temperatures do not permit these to be flushed out, however. This eventually causes the kidneys to fail, resulting in the tortoise to become comatose, which you would not notice owing to its hibernating state, and inevitably die.

These intermissions of winter activity in the wild are temporary and only necessary until the soil temperatures do not decrease to values of less than about 8C anymore. After the animals have warmed up, always in the immediate vicinity of their shelters, they will bury themselves superficially once more and reappear for basking if the next day is equally warm, or bury themselves deeper and resume their dormant state if temperatures decrease.

These brief stints of activity do not require the tortoises to consume food. Owing to the naturally rich fibre content in their diet, the gut is not entirely empty even during the winter months and so conserves the intestinal flora necessary for digestive processes. The animals therefore do not live off fat reserves stored, but rather first consume the remains of their last meals in the intestinal tract. As long as there is some food pulp left in the intestines, they will not suffer hunger either and therefore remain disinterested in food.

This illustration makes it plausible that tortoises kept in human care need to be accommodated, unlike in the wild, at hibernation temperatures that are constantly between 2 and at maximum 7C; in the case of Testudo horsfieldii, temperatures between 2 and 4C are ideal. Tortoises that are overwintered in captivity become uneasy at about 8C and will eventually exit their substrate. There, they will not find a warming sun that would bring their body temperature to a level where metabolism is possible, though. The metabolic functions that are started are incomplete, produce toxins, and sentence the animals to death.

At temperatures around 4C, the tortoises hibernate motionlessly and do also not execute motoric digging motions, which are in any case uncalled for in human care."

Instead of warm overwintering, they may have a S- Pelloponese, Tunisian or Almeria-type "winter". That way, one can avoid the danger of tortoise getting unnaturally fat overwinter and maybe avoiding the debut of pyramiding too.

In my opinion, in a flat, I would choose specifically the coldest room, with a good basking spot. I would even let the tortoise without heating for 3-4 days each, let's say, every 2 weeks. I do the same with my overwintering ones now- new pyramided arrivals, and a mature, superb ibera female that was very sick, and luckily found her in August in a yard, close to tortoise habitat- the Dobrogean city of Constanta. She would have been dead by now, if not. The "owner" agreed to give her to me.

In that termic regime, she- and all others- always resume feeding after no bulb for few days. Better cut the light in very cloudy days, to mimic the natural model- I observed often that, despite the same bulb/heat, they are incomparable active when the sun is shining too outdoors.
So, I excluded the ceramic night bulb and let nights be as cold as they get- in my case, not lower than 12*C.

It is a kind of hibernation, better than no hibernation at all. For an Ibera- it is warmer than usual, for an Almeria, Spain , or N-African Graeca- it will be quite similar. The days without heat will not be enough to favour damaging bacterial fermentation, since periodic awakening and restarting the "engines" will not allow that. And it will be safer than a true ibera brumation. Most tortoise people will advice to overwinter, if he's not fit.

Following this regime, you can feed him as much as the tortoise wants, since the active periods will alternate with sleeping days, so no danger of pyramiding, if you use only good weeds. He will have no growth and no weight loss this way, until Spring comes. So, by this method, you will have both safety and a mild, Mediterranean shore, interrupted brumation too.

Bathing in such potentially drying condition is required, once-twice a week (only when the tortoise is "hot and active"!), drinking water available all the time, and a hide with just a little moist substrate will be useful.

I hope that these informations will be useful for those overwintering HEALTHY tortoises, but suspected not 100% fit for a true hibernation- as late arrivals, or when hibernation is not possible from various reasons (lack of place, inexperienced enough keeper fearing of hibernation risks etc). Even not a temperate hibernation, that type of intermittent one helps a lot in slowing down the metabolism, preventing abnormal growth and helping in "reseting" the tortoise systems.

It is, as said, the type of hibernation met in the warmest places around the Mediteranean Sea- most North-African locations and only some European ones. It is better to have at least such an intermittent hibernation for your temperate tortoise than keeping them in a perpetual summer- that is for tropical species...

On the other hand, ill tortoises should be kept warm during treatments, summer regime, in order to allow the medication to work and the tortoise to keep his immune system running at peak parameters, and overwintering even after healing in the same warm conditions, until placed outdoors next spring.
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