ABSTRACT
In 1897 Amos Dolbear published a paper entitled The Cricket as a Thermometer, but was he correct? Can the behaviour of an animal be used to calculate the ambient air temperature?
The principle is now known as Dolbear’s Law, and has even featured in popular culture. The idea has been used with rattlesnakes; the speed of the rattle being correlated to temperature. Harlow Shapley was an immensely successful astronomer, but he published on the relationship of the run speed of ants and temperature, and even said that it was one of the most interesting points he had discovered in his scientific career.
The speed of ants, or the rattle of snakes’ tails, are influenced by the metabolic rates of the muscles of those animals and, being cold-blooded, the rate of cellular respiration is proportional to temperature. This has limits, with such animals becoming quiescent near freezing point of water and animals unable to withstand high temperatures (above approximately 40 oC), but between these limits animals can be used as surprisingly accurate thermometers. Of course, other thermometers are available, based on mercury or bimetallic properties, but the use of animals remains an interesting quirk of nature.
