Cold Blood vs Warm Blood


Is this hypothetical or proven?
If proven, HOW is it proven? Is an animal’s blood temperature taken?
I saw a show on Gallapagos turtles (terrapins?) who the narrator said were ASSUMED to be cold blooded, but exhibited many traits of warm blooded animals, and therefore, they weren’t sure what is was. If this were science, wouldn’t they know?

Thank you.

It partly depends on how you define “warm-blooded”, and it partly depends on what measurements you’re willing to take on a protected species. The Galapagos islands are near the equator, so the odds are that the Galapagos tortoise doesn’t have much in the way of adaptation to external temperature changes, and, on the other hand, they’re fairly large, which means that, merely by the laws of physics, they’ll tend to keep a constant temperature even without a specific biological mechanism (“mass homeothermy”).

Could you link to the
Cecil column this relates to please. :wink: Thanks.

I found a staff report What makes some animals cold-blooded and others warm-blooded? but no columns that would fit.

Welcome to the Straight Dope Message Boards, Paul, we’re glad to have you with us.

If you are commenting on a prior column or staff report, then it’s helpful to others if you provide a link to the column or starr report that you’re commenting on. This saves other readers lots of search time, and avoids repetition. No biggie, you’ll know next time.

On 'tother hand, if you are asking a brand new question, then the appropriate forum is the one called “General Questions.” And I sort of think that’s the case here. If so, I think the Staff Report that Kat has provided a link to will answer your question – that “cold blooded” and “warm blooded” are not, in fact, scientific terms and are not mutually exclusively categories.

Under the assumption that this is actually a General Question and not a response to Cecil’s column, I am moving the thread to the appropriate forum.

Again, no biggie, as you post here more and read posts, you’ll catch on. Welcome!

And it’s also important to note that scientists do indeed literally physically take the temperatures of animals.

The old-fashioned definition of cold-blooded vs. warm-blooded depended on this. Warm-blooded animals used internal heating devices to keep their temperature at a constant high level. Cold-blooded animals’ temperatures, on the other hand, varied considerably. They would raise their temperatures by sitting out in the sun, for example, and then use that extra energy for predation or fighting. Their internal temperatures would then cool down and they would lay in torpor. The highest levels their temperatures would reach might well be higher than a warm-blooded animal’s temperature, but it would not last.

More extensive research has shown that this sharp division is not completely reflective of the complexity of nature. There are middle-ground mechanisms that apply to some animals. Perhaps Galapagos tortoises are one of them. Many paleontologists now think that dinosaurs were neither strictly warm-blooded nor cold-blooded, but somewhere in between. Understanding the true complexity of nature even if it supplants the simplified stories in old high school textbooks is a feature of science, not a bug.

As my staff report says, cold-blooded and warm-blooded are non-technical terms. However, it is proven that some animals are able to maintain their body termperatures above the external temperature. Many of them use internal sources of heat to do this.

Yes, among many other methods, including measuring its respiration and metabolism.

Since I don’t know exactly what they meant by this, I can’t really answer it definitively. Galapagos Tortoises are definitely “cold-blooded” poikilothermic ectotherms in a broad sense. I expect that, like many reptiles, they show some behavioral thermoregulation, and because of their body size they will gain and lose heat slowly. Therefore it is likely that they may often maintain a body temperature significantly above the external temperature and hence be somewhat homeothermic. This is possibly what they meant. I have never heard that Galapagos tortoises might be endothermic to any extent.