IR Camouflage at TL 0 - 1

[Flyndaran]

Eyes are energy hungry sensors. I believe that crocodilians use complex circulatory features to keep eyes warm when under water so they can clearly see prey.
So eyes on stalks would still need lots of warm blood to function.

[Flyndaran]

Originally Posted by vicky_molokh

How do vampire bats work? They have some sort of insulation between their IR sensors and the rest of the body, or something like that.

Real world animals use heat sensors rather than precise IR vision.
Vampire bats hijack and boost their heads' heat/pain receptors acuity to absurd levels allowing detection at range. This has the odd effect that they had to lose the ability to detect any kind of pain on their heads or be in constant agony.

[Anthony]

Originally Posted by vicky_molokh

How do vampire bats work? They have some sort of insulation between their IR sensors and the rest of the body, or something like that.

First of all, it's not entirely true that the heat sensor has to be cooler than the thing it's sensing -- it just has to be cool if you want to be good at sensing. Realistically, you aren't going to get IR performance on the scale of the GURPS advantage without cryogenic cooling and 2" optics, so presumably anything TL 0-1 with the IR vision advantage has a supernatural power. Secondly, not all parts of the body are at the same temperature, they probably use some sort of membrane that tends to cool to near ambient (and is thus rather vulnerable to frostbite, though I don't think vampire bats live anywhere where that will be a problem).

[vicky_molokh]

Originally Posted by Flyndaran

Real world animals use heat sensors rather than precise IR vision.
Vampire bats hijack and boost their heads' heat/pain receptors acuity to absurd levels allowing detection at range. This has the odd effect that they had to lose the ability to detect any kind of pain on their heads or be in constant agony.

That's the evolutionary paths found on Earth, yes. I'm not sure why a different path would be actually impossible (e.g. dedicated nerves and receptors that differ from pain/generic heat nerves and receptors).

[Flyndaran]

Originally Posted by vicky_molokh

That's the evolutionary paths found on Earth, yes. I'm not sure why a different path would be actually impossible (e.g. dedicated nerves and receptors that differ from pain/generic heat nerves and receptors).

Evolving completely new types of nerves and senses is very unlikely. But I just thought it an odd bit of trivia about vampire bats. They are a very interesting group of species.

[Flyndaran]

Originally Posted by Anthony

...(and is thus rather vulnerable to frostbite, though I don't think vampire bats live anywhere where that will be a problem).

They will die long before they get anywhere near that cold... and die if they get too hot. They actually have a very narrow range of survivable temperatures, because they have almost no body fat, and are metabolically hyperactive.

[walkir]

Okay, that sounds as if I best forget the whole idea of camouflage for them, then as inventing camouflage that can be easily circumvented by looking at it would be pretty pointless.

Except for things that allow to blend in better or when dealing with opponents that do not have the sense (going to hunt lunch, mostly), that's something I keep in mind.

[jacobmuller]

Originally Posted by Jovus

Really? Do you have any research I can look at for that?

I'm not disbelieving you; I'm just curious, because this is something I haven't heard before, and so I want to see how and why it works that way.

Look at the Mythbusters clip tagged in post#12. They heat the room and go in naked but it sets off the sensor - different parts of your body are different temperatures.

[Flyndaran]

Originally Posted by jacobmuller

Look at the Mythbusters clip tagged in post#12. They heat the room and go in naked but it sets off the sensor - different parts of your body are different temperatures.

IR vision can tell the difference between identical twins as they developed slightly different blood vessel patterns.