A.E. Dolbear, a professor at Tufts College, first noted the relationship between ambient temperature and the rate that a cricket chirps. Crickets chirp faster as temperatures rise, and slower when temperatures fall.
Dolbear published the first equation for using crickets to calculate temperature in 1897. Using his equation, called Dolbear's Law, you can determine the approximate temperature in Fahrenheit, based on the number of cricket chirps you hear in one minute.
T = 50+[(N-40)/4]
T = temperature
N = number of chirps per minute
Chirping rates of crickets and katydids also vary by species, so Dolbear and other scientists devised more accurate equations for some species. The following table provides equations for three common Orthopteran species. You can click on each name to hear a sound file of that species.
Source for equations: University of Nebraska-Lincoln Entomology Dept.
Equations for Calculating Temperature Based on Cricket Chirps
|Field Cricket||T = 50+[(N-40)/4]|
|Snowy Tree Cricket||T = 50+[(N-92)/4.7]|
|Common True Katydid||T = 60+[(N-19)/3]|