Why not we go for some other methodology (in my aquarium i have seen a strange thing, one of the fighter fishes change colour as the water cools down) -

Fish being cold blooded may be a few dinosaurs could have had the same feature (hopefully not T Rex)

These might have been put as pet thermometers

Here putting the fish will be non ethical, and no dinosaurs available what if we ask the experimenter to walk out in underclothes (no nudity please) and the frequency of his chatter may be a measurement of the temperature no PETA can object to this.

(ofcourse We have to calibrate the instrument)

PS: Just remembered - this line would not work (see ice-age) - no dinosors - all of them died when the ice age set in. The licker must have been a rat - found the paper and the gum tasty (they usually find it)

In my factory one had eaten through the cable of the CNC machine and has rattled us for more than a fortnight (we have replaced the cable with armored and now we specify armored external cabling for all machines we buy)

PS2 : I really loved my definition. Googled for my name and got it from the original movie, just a few tweaking here and there.