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"...We assessed heat production, at a constant environmental temperature, by taking infrared (IR) images of snakes during fasting and after being fed meals varying from 10% to 50% of their own body masses. Our results show clearly that digesting rattlesnakes have significantly increased body temperatures, even when precluded from adjusting their thermoregulatory behavior. The feeding-derived thermogenesis caused the surface body temperature of rattlesnakes to increase by 0.9-1.2 degrees C, a temperature change that will significantly affect digestive performance. The alterations in body temperature following feeding correlated closely with the temporal profile of changes in post-prandial metabolism. Moreover, the magnitude of the thermogenesis was greater for snakes fed large meals, as was the corresponding metabolic response. Since IR imaging only assesses surface temperatures, the magnitude of the thermogenesis and the changes in deep core temperature could be even more pronounced than is reported here."
The temperature increase may seem minuscule, but for a snake, it is probably significant, and it adds credence to some of the sites that state that snakes will forego heading for the hot hide for a time just after eating, but will eventually head there later.
Quote:
Originally Posted by MesoCorney
That would suggest they are endothermic, which goes against everything I know about reptiles. I would like to see where you read about that.
"Surprise rise
The team studied the Argentinian black and white tegu (Salvator merianae), a 60-90-centimetre-long lizard that lives across much of South America.
As expected, for much of the year it cooled down when the sun set, reaching a low similar to that of its burrow between about 4 and 6am.
The surprise came when the lizards reached the reproductive time of the year, from September to December. During the cold early hours of the morning in that season, their breathing and heart rates rose and their temperatures reached as much as 10 °C above those of their burrows.
The discovery was so unexpected that the scientists took a further three years to confirm it, says Tattersall. “We would expect them to be as cold as they possibly could be at that time,” he says." - From the tegu article.
I would imagine that many other reptiles have similar adaptations that have simply just gone unstudied.
However, outside of the random one off instances that we've mentioned here in general they can’t fuel sustained muscular activity by aerobic means, but they have a fallback, as anaerobic metabolism usually can keep them going long enough to find the food item or shelter that they require. This is likely the extra umph they need to push themselves into hibernation chambers in the wild or out on cold days in the early spring as we see with garter snakes and others.
When a snake digests food there is extra energy and that generates heat on its own, now that's not to say that energy is enough to maintain proper body functions over a long period at extremely sub optimal temperatures. But it does lend itself to explaining why hotspots (in snakes) may not be necessary for proper digestion if kept at either the correct single ambient temperature or even with a gradient minus the hotspot, so say 75-85 with no little spot that's 90 degrees or whatever.
I do think, in particular the biochemical hypothesis with the alligator study I mentioned is interesting. A highly debated subject in regards to dinosaurs is whether they were endo or ectothermic. Crocodilians as we know are considered to be one of the most ancient of the living reptiles, having many relatives from back when dinosaurs still roamed the land. Perhaps dinosaurs had similar functions in regards to temperature, maybe some were fully endothermic and maybe those species evolved into birds and mammals while the ectothermic dinos evolved into the reptiles, amphibians we see today.
But, fish who all of those species evolved from, would endothermic fish have evolved into the warm blooded dinos and cold blooded fish into the cold blooded dinosaurs. Honestly, probably something entirely different, I'm not an archaeologist, I know more than probably most of the population about dinosaurs but considering the majority of the population doesn't care about dinosaurs that doesn't say much.
But in the tegu article there is a link to another surprising discovery in regards to fish generating their own heat.
The opah species of fish has a few adaptations that generate and spread heat throughout its body in order to dive into extremely cold waters to feed and such. Is this or the dinosaur thing related to our discussions, no, not really. But I think it's interesting.
But while we're on the topic of fish, in particular captive aquarium fish. These animals are ectotherms just like our reptiles. We know for a fact that fish thermoregulate in the wild to avoid too warm of water or too cool temperature water, yet in captivity we don't offer multiple temperature levels (at least intentionally). The aquarium hobby decided that in general 76-80 is the best area to be in and they've essentially stuck to that. This is because it's not possible or realistic to have any sort of real gradient in all but the largest aquariums which I imagine could be done with creatively placed heaters. We know that fish thermoregulate, we know they don't need to. So we don't make it an important aspect of that hobby.
I pose the question, if for whatever reason any of the keepers here were unable to provide thermoregulation opportunities, would they suddenly stop keeping snakes? Or would we as a hobby just adapt to the ambient temperature method because we know the snakes don't need it and others have found success with the method?
In my opinion offering snakes something they don't need is adding another variable that can cause problems. A snake NEEDS a reasonably sized tub, a certain temperature a water bowl and some hides.
I choose to provide natural decor, many hides, burrowing opportunity. I feel as if I'm doing that more for my enjoyment than anything the snake needs. I want my snakes to have more room to stretch out, move around and to have the decor to climb and display on. Does the snake NEED it? No. Does the snake WANT it? Eh, that's arguable. Do I want my snakes to have those opportunities? Yes. In regards to my snakes I don't want them to have access to hotspots or a huge gradient. This is because of the problems that I've found to be associated with those aspects of care, it's in the interest of my snake's health more than anything. I think that snakes in the wild chase the temperatures I'm offering my snakes making it natural without all of the extremes they are forced to face in the wild which in my mind is the benefit I offer my snakes from being in captivity.
Well that got wordy with a tangent here and there and I don't have a conclusion so I won't put one lol.
Once again from the world of tortoises, but tortoises "generate heat" after eating too. However, it is my understanding that it is not the tortoise that creates the heat but the gut flora and fermentation process that accompanies digestion in hind-gut fermenters. Something similar could be true for the crocodilians, tegus, and rattlesnakes... they are not producing heat like exotherms but if their gut flora is given fuel then the microorganisms may generate heat or initiate chemical processes that create heat. It would also make sense that larger meals result in more heat, the microorganisms have more fuel to work with.
I'm afraid that I don't have a citation for the tortoise heat generation, it has been a couple years since I read about it.
Once again from the world of tortoises, but tortoises "generate heat" after eating too. However, it is my understanding that it is not the tortoise that creates the heat but the gut flora and fermentation process that accompanies digestion in hind-gut fermenters. Something similar could be true for the crocodilians, tegus, and rattlesnakes... they are not producing heat like exotherms but if their gut flora is given fuel then the microorganisms may generate heat or initiate chemical processes that create heat. It would also make sense that larger meals result in more heat, the microorganisms have more fuel to work with.
I'm afraid that I don't have a citation for the tortoise heat generation, it has been a couple years since I read about it.
I'm not a scientist but your explanation for the snakes and tortoises is probably sound. I was just pointing out that they get warmer, I think with the crocs and tegus if feeding was causing it the people studying them would have seen that and I believe the tegus were on their way right out of hibernation so wouldn't have any food in them.
The whole subject is really interesting in general especially when you get down to the science-y parts of it. I'm not really defending the no hotspot or ambient temperature thing anymore, I just think the discussion is really interesting especially when people start whipping scientific papers around.
I wish that these journal study sites weren't so dang expensive, that's where the juicy stuff that doesn't make it into random reptile books is hidden lol. Can we get a forum wide account?
Reptiles are just so interesting in general.
Even the definitions of Ectotherms and Endotherms both start off with "so-called cold blooded" and "so-called warm blooded" and I'm not trying to get into a semantics argument here... but ectotherms do rely on external temperatures and endotherms do maintain their own temperature independent of the environment. But even endotherms rely on external temperatures to a certain extent and maybe even ectotherms can't be 100% reliant on external temperatures otherwise any random cold spell during springtime could wipe them out.
Even a mammal has a similar adaptation to the woodfrog:
From Business Insider: The link is to the sourced study
Arctic ground squirrels are the only mammal on this list, and for good reason. Although many mammals can handle the cold with downy coats of fur, and by hibernating away the cold months, none shut down for the winter like the arctic ground squirrel. Like the other contenders, these squirrels can also super-cool their bodies below its freezing point, down to -2.9° C (26.78° F), a record amongst mammals.
But the real impressive adaptation happens in the squirrels' brains — they can sever neural connections, synapses, for hibernation, and reconnect them as soon as they wake (and warm) up, roughly once every two or three weeks during the winter.
Dendrites are the branchlike portion of neurons that receive chemical messages from other neurons, and hibernation causes them to wither. A Russian study in the early 1990s found that dissected brains of squirrels mid-hibernation contained far fewer dendrites than the brains from squirrels that were woken up and allowed to acclimate.
And only two hours after waking from its slumber, the synapse connections are restored, with even more dendrite branches than before. But 12 to 15 hours later, the brain begins culling the connections again as the squirrel returns to hibernation.
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Back in regards to turtles, here is a video that is regarding captive turtles kept outdoors at Garden State Tortoise and the keeper has seen his Blanding's turtles are active in the 20F range. Towards the end of the video the keeper Chris Leone mentions that the Gulf Coast box turtles winter outside in New Jersey as well. It's kind of interesting the statement Kenan makes in regards to the genetics being decided long ago in regards to the conditions that box turtles can endure. Now, does this mean that we can drop a snake neck turtle from South America in a pond in Ohio where I live and expect good things to happen? No, absolutely not but I wonder how the ideal captive temperatures of various species of aquatic turtles measure up to one another and then furthermore what the keepers of multiple species are actually doing in practice that is working for them and their turtles.
Since mention was made of ratlesnakes, I thought I'd throw this out there. Scientists were trying to figure out how a certain species of rattlesnake could survive in sub-freezing temperatures and digest it's food.
They basically force fed one of these rattlesnakes and studied it under conditions mimicking it's habitat. After a period of time, they had to take emergency action to save the snake.
Well, they missed ONE thing! In the wild, rattlesnakes invenomate their prey which initiates and assists the digestive processes. They injected prey with venom and repeated the experiment with much success.
Since mention was made of ratlesnakes, I thought I'd throw this out there. Scientists were trying to figure out how a certain species of rattlesnake could survive in sub-freezing temperatures and digest it's food.
They basically force fed one of these rattlesnakes and studied it under conditions mimicking it's habitat. After a period of time, they had to take emergency action to save the snake.
Well, they missed ONE thing! In the wild, rattlesnakes invenomate their prey which initiates and assists the digestive processes. They injected prey with venom and repeated the experiment with much success.
Do we know whether they are actively feeding in sub-freezing temperatures in the wild? I'm no rattlesnake expert but I think that's really cool. Not just a, can they but do they kind of question.
If we think about the places these snakes are found, in North America at least (or even just North American Snakes in general) in regards to when the last ice age ended, 11,700 years ago is what google craps out from livescience. Potentially with a catastrophic meteor related event 13,000 years ago that might have wiped out the mega mammals and some prehistoric civilizations.
My question is this. Could the snakes have been alive in some of the areas very close to the ice sheets during this time period? Were these adaptations with the rattlesnakes, the crocodiles etc, a way for them to survive the colder climates brought on by the ice age? How much can a population REALLY change, genetically speaking, in the span of only a few 10's of thousands of years? The only source I can find on the ice sheets is estimated maps and generalized estimates of what temperatures were doing back then. The average accepted number I keep seeing is that overall average temperatures were lower by 10 - 40 degrees depending on area and what climate cycle was happening at the time.
Here's an forum conversation with some guy who wrote a book on pre-historic Georgia. Apparently weather hobbyists are a thing as well, he even has articles on reptile and amphibian fossils from that era.
How far north did reptiles, snakes in particular live during this time? Particularly out west? I'm gonna try and do some more research and see what I come back with as I think it is certainly interesting in better understanding more in general.
This information came from a TV show I watched. The whole point of the research was to figure out how these rattlesnakes could survive in the climate they were in..
I wish I could offer more, but it's been a few years.
This information came from a TV show I watched. The whole point of the research was to figure out how these rattlesnakes could survive in the climate they were in..
I wish I could offer more, but it's been a few years.
Hehe, I always hate that. Sucks that a lot of the older sites with interesting reptile information is gone, old books aren't at the library anymore etc. Random one off tips from actual breeders at shows and such.
Not offering a hot spot makes no sense at all honestly I have no idea why that's even a thing? They need to thermo-regulate. That's like saying I spoke to a well respected doctor who has survived on heroin. Sorry I don't get it but to each there own.
Not offering a hot spot makes no sense at all honestly I have no idea why that's even a thing? They need to thermo-regulate. That's like saying I spoke to a well respected doctor who has survived on heroin. Sorry I don't get it but to each there own.
Guy said he spoke to a well respected snake breeder who said snakes don't need a hotspot? My point was simply that totally stupid, cold blooded animals need heat!! That's not really a debate topic lol ok the analogy I used wasn't the best but I was so blown away i could of went on for days. If your going to get an animal any animal get everything it needs or just simply don't get it.
I'm sure the guys whole argument was they eat and breed so they are fine that's where the heroin analogy came in some people do it an live don't mean everyone who does it will live or that it's a good idea, he is lucky his snakes lived or didn't get sick at the very least.
And what is your experience...how many years have you been keeping reptiles? How many snakes do you have...how many different species? How can you call someone "stupid" when you don't back up your statements with nothing other than that strange analogy about heroin and a doctor? You've heard the phrase, "comparing apples to oranges?" I don't see where an opoid abusing medical professional has anything to do with herpeculturists and reptile husbandry.
Quote:
Originally Posted by Louv44
Guy said he spoke to a well respected snake breeder who said snakes don't need a hotspot? My point was simply that totally stupid, cold blooded animals need heat!! That's not really a debate topic lol ok the analogy I used wasn't the best but I was so blown away i could of went on for days. If your going to get an animal any animal get everything it needs or just simply don't get it.
I'm sure the guys whole argument was they eat and breed so they are fine that's where the heroin analogy came in some people do it an live don't mean everyone who does it will live or that it's a good idea, he is lucky his snakes lived or didn't get sick at the very least.
what??? 
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