Along with your next post, please post pics of your tortoises and give us a run down of the way you raise yours and what part of the country or world you do this in, please.
Team Gomberg said:When you take temperature and humidity readings, what level do you sample? Measuring from 6' above the ground will have different readings than measuring under a bush or at the base of thick grass. The moisture at the leopard hatchling level is much higher.
wellington said:Along with your next post, please post pics of your tortoises and give us a run down of the way you raise yours and what part of the country or world you do this in, please.
Testudoresearch said:Tom,
I have read your reports of your experiences with G. pardalis and G. sulcata in various threads posted here. I note you recommend rearing in a high humidity environment. Your results are interesting, and I applaud your tenacity in pursuing this research. Your results are meaningful and useful. However.... I do believe that you may be misinterpreting certain causes and effects. I also note that you state, above, that you believe in some form not only of external, but some form of "internal" or"cellular" dehydration as one of the causes. This would be quite remarkable, because physiologically, it would be unique in the animal kingdom. No such process is known to science. Living cells, within an organism, are invariably in a state of homeostasis - and if dehydrated to the point of "collapse", as proponents of the theory you appear to subscribe to suggest, then they would be no longer living cells, but dead cells. There is no cytological evidence, anywhere, that this is occurring.
The areas just below the outer keratin are very well supplied by numerous blood vessels. The underlying bone too, is also well supplied and is invariably at homeostasis. If any localised "drying" did take place at that level, it would cause cell death and localised necrosis. Examination of numerous 'pyramided' carapaces fails to reveal any such condition.
So, I think we have to look beyond that theory (which remains a theory, as absolutely no-one has produced a sliver of real, hard evidence to support it). This is particularly important when a theory contradicts the established physiological and biological sciences.
I have two questions.
The first concerns Leopard tortoises in the wild which exhibit a type of raised scute phenomenon. I note you have said that you believe these are most probably ex-captives that have been released into the wild? (I hope I am not misquoting you here). While I have no count that this does occur (I have studied G. pardalis in South Africa), I believe it highly improbable it accounts for all of them - by a long way. Furthermore, there are numerous specimens in natural history museums, some dating back almost 200 years, that display identical scute formations. These were collected, in many cases from extremely remote areas, long before anyone, anywhere was keeping these animals in captivity. This is significant evidence. In the same context, it is useful to look at another species from the same part of the world, Psammobates tentorius (the Tent tortoise). These display, as a matter of course, very similar scute formations to some of these wild Leopards tortoises. Clearly, they are not all ex-captives, and again, we have collection material going back a very long way. It is quite clearly normal for them - not a result of any pathology or incorrect environment. How do they fit into the scheme of things, and if it is normal for them, why is not possible that it might also be normal for some populations of G. pardalis?
My second question is more of a practical nature. You are using a very high humidity environment to rear G. pardalis. I understand you have seen these natural habitats... if so, you must surely recognise that the environment you are using is totally different from that in the wild. It is, in general, a semi-arid, scrubby habitat. Finding pockets of high humidity in that habitat is very, very difficult. I have recorded the actual conditions right next to both juvenile and adult wild Leopard tortoises, and typically, RH ranges from 35-60% for most of the year. Very high levels are only seen at certain times of year, during and immediately following rain. For most of the time, RH is in the 40-50% range.
So as far as this goes, I have to question why people feel that such an entirely different set of microclimate conditions from that in the wild are needed in captivity? Surely, it should not be necessary. An intensely artificial method is being used here that bears almost no relation to conditions this species experiences in nature, in its natural habitat. It is important to enquire why, and what else is going wrong that demands such an approach?
Thank you for your time. I do believe these are important questions that all serious keepers and investigators have an interest in seeing addressed.
wellington said:Along with your next post, please post pics of your tortoises and give us a run down of the way you raise yours and what part of the country or world you do this in, please.
Testudoresearch said:Tom,
I have read your reports of your experiences with G. pardalis and G. sulcata in various threads posted here. I note you recommend rearing in a high humidity environment. Your results are interesting, and I applaud your tenacity in pursuing this research. Your results are meaningful and useful. However.... I do believe that you may be misinterpreting certain causes and effects. I also note that you state, above, that you believe in some form not only of external, but some form of "internal" or"cellular" dehydration as one of the causes. This would be quite remarkable, because physiologically, it would be unique in the animal kingdom. No such process is known to science. Living cells, within an organism, are invariably in a state of homeostasis - and if dehydrated to the point of "collapse", as proponents of the theory you appear to subscribe to suggest, then they would be no longer living cells, but dead cells. There is no cytological evidence, anywhere, that this is occurring.
The areas just below the outer keratin are very well supplied by numerous blood vessels. The underlying bone too, is also well supplied and is invariably at homeostasis. If any localised "drying" did take place at that level, it would cause cell death and localised necrosis. Examination of numerous 'pyramided' carapaces fails to reveal any such condition.
So, I think we have to look beyond that theory (which remains a theory, as absolutely no-one has produced a sliver of real, hard evidence to support it). This is particularly important when a theory contradicts the established physiological and biological sciences.
I have two questions.
The first concerns Leopard tortoises in the wild which exhibit a type of raised scute phenomenon. I note you have said that you believe these are most probably ex-captives that have been released into the wild? (I hope I am not misquoting you here). While I have no count that this does occur (I have studied G. pardalis in South Africa), I believe it highly improbable it accounts for all of them - by a long way. Furthermore, there are numerous specimens in natural history museums, some dating back almost 200 years, that display identical scute formations. These were collected, in many cases from extremely remote areas, long before anyone, anywhere was keeping these animals in captivity. This is significant evidence. In the same context, it is useful to look at another species from the same part of the world, Psammobates tentorius (the Tent tortoise). These display, as a matter of course, very similar scute formations to some of these wild Leopards tortoises. Clearly, they are not all ex-captives, and again, we have collection material going back a very long way. It is quite clearly normal for them - not a result of any pathology or incorrect environment. How do they fit into the scheme of things, and if it is normal for them, why is not possible that it might also be normal for some populations of G. pardalis?
My second question is more of a practical nature. You are using a very high humidity environment to rear G. pardalis. I understand you have seen these natural habitats... if so, you must surely recognise that the environment you are using is totally different from that in the wild. It is, in general, a semi-arid, scrubby habitat. Finding pockets of high humidity in that habitat is very, very difficult. I have recorded the actual conditions right next to both juvenile and adult wild Leopard tortoises, and typically, RH ranges from 35-60% for most of the year. Very high levels are only seen at certain times of year, during and immediately following rain. For most of the time, RH is in the 40-50% range.
So as far as this goes, I have to question why people feel that such an entirely different set of microclimate conditions from that in the wild are needed in captivity? Surely, it should not be necessary. An intensely artificial method is being used here that bears almost no relation to conditions this species experiences in nature, in its natural habitat. It is important to enquire why, and what else is going wrong that demands such an approach?
Thank you for your time. I do believe these are important questions that all serious keepers and investigators have an interest in seeing addressed.
Team Gomberg said:Raising Testudo is different than raising Sulcata and Leopard tortoises.
This high humidity method doesn't apply to your species.
You tortoises look great but they are comparing apples to oranges.
Team Gomberg said:You don't think different species can have different husbandry requirements? I do.
Tom said:To address your opening paragraphs: As I stated in sentence 1 of my reply, the cellular pressure theory is simply something that I have read that could explain what we see in captivity. You state that cells are either fully hydrated, or dead, as if their is no in between. Haven't you ever seen a wilted plant? Haven't you seen that wilted plant perk back up with the addition of water?
Tom said:Again, I have no idea what is really happening with those pyramided cells on a physiological level, I only know what I've seen right in front of my own eyes hundreds or thousands of times.
Tom said:Your first question: I never said that pyramiding in wild leopards does not exist. I have made the point that many "wild" ones were started dry in captivity and this could account for some of the "wild" pyramided leopards that have been seen. Truth be told, no person, you or me included, really knows the answer to this. I don't know how many, or to what degree, "wild" leopards do or don't pyramid, and neither do you. Some of them, a little bit? Probably. All of them, or a lot? No.
Tom said:There has never been a wild one that looks like the absolutely grotesque ones that have been produced in dry indoor North American enclosures.
Tom said:I have never commented one way or another on tent tortoises as I have no experience with them at all. We have a member here named Will who has seen and studied them in the wild, and he has generously shared his experiences and knowledge about them. From what he has posted it appears that some pyramiding is "natural" for that species.
Tom said:For your second question: It should be noted that this IS a much more muddled case with G. pardalis than it is with G. sulcata due to the wide variation in wild leopard habitats, where sulcatas have much more homogenous seasons and weather patterns through out their range. I was in and around Cape Town and George for about four months from late March to June. I keep my South African leopards in very similar conditions to what I observed in South Africa.
Tom said:The people who wrote the books on sulcatas also researched the climate over there extensively. They erroneously based their care info on their incorrect assumptions. Leopard tortoise book writers did the same thing. Where did this gets us all? It got us two decades of horribly pyramided, dehydrated captive tortoises.
Tom said:SOOOOOooooooo, rather than focus on what can or can't be known about what happens in the wild, rather than trying to simulate what we think happens in the wild for leopards, since that tactic failed for decades
Tom said:For nearly 20 years I, and everyone else failed to produce a smooth leopard or sulcata..
Tom said:Lastly, if you can raise a leopard or sulcata smooth and healthy in a dry environment, you are someone I would like to learn from. If you have done this, I would ask that rather than point out how I am wrong about this, that and the other thing, please demonstrate how you did it and show the results.
julietteq said:I have the feeling nobody knows at this point why tortoises pyramid more often in captivity then in the wild. Until we do, I feel it is important to take Tom's advise to make sure humidity levels are up in the torts home. Since Tom is so succesful raising his torts, there must be some link to water/humidity. Maybe the extreme humidity in captivity compensates for circumstances in the wild that are so in front of our face that we do not see it? I personallly thought the comment about the "sandblasting/wear and tear on the shell" was very interesting.
Lets compare it to humans, when you have a deskjob, your nails (ceratine) need clipping. However when we were hunter/gatherers I doubt we needed manicures! Your nails become brittle when you are in a bath and they break off very easy. Maybe that is what the humidity does. It makes the carapace soft so it wears down easier and thus prevents pyramiding?
PS: I assume we are all normal people and nobody will start "sanding" off their tortoise shells!!!!
Testudoresearch said:Well, if I could just point out that the title of this thread is very clear. It is "What is the physiology behind pyramiding". That is precisely what I am here to address. I was referred to the forum by a colleague who does follow it and thought that it might be helpful if I contributed on this subject, as it is the topic of a new publication I have pending. Having viewed some of the comments on the topic, it is very clear to me that there is a lot of confusion and misunderstanding. All I really wish to do is to highlight some new information that does shed considerable light on the physiological mechanisms involved.
I do not believe endless anecdotes on husbandry, from me or anyone else, are really that productive in this context. It is far more to the point to try to understand exactly why and how this class of deformity really occurs. Once that is understood, it becomes much easier to determine appropriate husbandry. I do not feel that it is very satisfactory to advance specific husbandry advice when you cannot adequately explain why a particular method works (or not). Guessing is not the same as explaining. You must be able to present a viable mechanism. That must be credible from both biological and physiological perspectives. In short, it must make scientific sense. If it does not do so, then something is wrong or a piece of the puzzle is missing.
It is also not hugely productive to debate in great detail all the specific habitats used by tortoises on internet fora. The only reason I raised this is because many false assumptions are being made. In respect of G. pardalis, the prime habitat in SA is "semi-arid karoo veld". This has a specific meaning. I highly recommend anyone interested in finding out more for themselves to consult "Karoo Veld - Ecology & Management" by Milton and Dean (Fitzpatrick Institute, University of Cape Town). This provides a superb overview of the region, and even includes detailed precipitation and climatic maps that can be overlaid with tortoise distribution data. It is a very useful reference for anyone remotely interested in South African tortoises.
I included a photo of one of my tortoises simply because I was asked to. I have reared numerous examples, and I think this does show that very good growth can indeed be achieved without recourse to extreme measures and incredibly high levels of RH. Some have claimed this is not possible. I ask you to judge for yourselves. This one was photographed at 4 years of age. Not only does it look good, but bone mineral density was excellent, as confirmed by a dual-energy x-ray absorptiometry (DEXA) scan.
The problem is that you can have what appear to be very smooth tortoises externally, but which internally, have very poor bone mineral density - with fibrous lesions and poor mass. So, establishing the condition of bones generated under various husbandry regimes is absolutely critical. Yet, it is rarely done.
It is intriguing that so many keepers hold totally contradictory views on these matters. On the one hand, we have people who say that Leopard and Sulcata tortoises need this super high humidity regime, but Testudo do not... and then other keepers who enthusiastically argue the exact opposite. What I think many miss is that in the paper by Weisner and Iben (cited extensively by Richard Fife), they did not limit their argument to G. sulcata, but claimed it affected multiple species: "Many species of tortoises live most of their lives hidden either in caves (e.g. Testudo horsfieldii, Gopherus sp.) or on the ground surrounded by high humidity even during arid conditionsâ€.
Unfortunately, this is plain wrong. It is useful they included Gopherus, because we have superb microclimate data for this species, including burrow humidity throughout the year. In the most detailed and comprehensive study yet carried out on Desert tortoise burrows in Nevada, Bulova (2002) established accurate environmental data for more than 70 individual burrows over an extended period and recorded burrow relative humidity levels ranging from 6.1 to 44.5%, compared to surface relative humidity levels of 4.1 to 32.2%. Other data, from other researchers in various localities for these species totally confirms this. This data conclusively destroys the argument that these tortoises experience sustained levels of RH above 80% in nature (the authors of that paper actually recommend provision of RH up to 100%!!)
There is no doubt, however, that humidity affects tortoises, and can influence the way in which a carapace develops. This is where physiology and ecology collide, and where the answers are to be found.
To do that we need to look closely at the physical structure of the tortoise skeleton and carapace, and in particular at the properties of the materials it is built from. How those materials respond to the environment, and to various mechanical stresses, is key to developing a viable explanation for the physiology of pyramiding.
I will shortly post some images of carapace sections for comparison and also explain what we have discovered concerning those interactions.