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I read that pit vipers can detect temperature differences as slight as 0.02 degrees C, that they have the most developed heat pits and that the heat pits of boids perform in the same way. I also understand that the pits allow snakes to sense changes in the ambient temperature.

My question is, does this mean they can sense any body temp of an animal if it's different from the ambient temp? Or do boids only sense items of a certain minimum temperature? Or of a certain temperature difference from the ambient temperature? I know the pits help them hunt warm blooded animals, but does that necessarily mean they can only sense warm blooded animals (and not cold blooded)of a certain temp?
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They can sense anything that is .02 degrees F (or more) warmer than its surroundings. So, it there is a lizard that is slightly warmer that it's surroundings they can zero in on it. It doesn't matter if the animal (or object) is warm blooded, cold blooded or inanimate.
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We do not inherit the Earth from our ancestors; we borrow it from our children. Ralph Waldo Emerson

Wow! That was quick - what service! LOL

Thank you!
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Check Out My Albums

1.0 Ball Python "Aragorn"
1.0 Kenyan Sand Boa "Gimli"
1.0 Saharan Sand Boa "Frodo"
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1.0 San Felipe Rosy Boa "Legalos"
0.1 California Kingsnake "Gentoo"
1.0 Mexican Black Kingsnake "Indigo"
1.0 Snow Corn snake "Chile"
0.1 Okeetee Corn snake "Amazon"
0.0.1 Crested Gecko
0.0.1 Irian Jaya BlueTongued Skink
0.1 Australian Cattle Dog/Pointer "Kira"

I'm sure, like most of the temperature receptors in your body, there is a certain threshold temperature at which they begin to fire. I suspect they work by firing more frequently when exposed to warmer temps, so the snake can discriminate between temperatures by how frequently the impulses arrive at the brain. Fast impulses means warmer temps.

If that is the case, there ought to be a temperature where the impulse rate is low enough that it doesn't stimulate the nerves to carry the signal to the appropriate part of the brain.

So while a snake may be able to sense the difference between something that is 25°C and 25.5°C, I don't know whether the same receptors would fire to distinguish -25°C from -24.5°C. I am sure that there is a threshold below which which they do not fire.

Now, would that temperature be within the normal activity range of the snake? Probably not. But at least theoretically, there is a temperature minimum for them.
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Chris Harrison