Cricket chirps
/15 sec
Temperature
°F

# Crickets Chirping Thermometer

By Hanna Pamuła, PhD candidate
Last updated: Aug 12, 2019

With this crickets chirping thermometer, you can estimate the temperature outside counting only crickets sounds in the time unit. It may sound like a joke, but these are real studies - the short article The Cricket as a Thermometer was published in 1897. Its author proposed the formula associating cricket chirps and the temperature, now known as Dolbear's law. Give this calculator a go or keep reading to understand how do crickets chirp, why do they do that and even to find out how to stop crickets from chirping.

## Dolbear's law

In the late 19th century, physicist Amos Emerson Dolbear noticed that the crickets on the field are singing at the same rate. He made observations and created a formula describing the relationship between air temperature and the rate at which crickets chirp. Mr. Dolbear was an inventor and a great scientist: he produced the first telephone a decade before Bell's patent (but he couldn't prove his claim), patented the wireless telegraphy system that was a milestone for Marconi in the radio invention, authored several books and articles. He's a bit forgotten and neglected in science history books, so at least he has a law named after him. That's the irony of life: Dolbear's law is about crickets and temperature, not about the author's main love and field of interest - physics.

## Cricket chirps temperature formula

Simply speaking, the higher the temperature is, the higher is the rate at which the crickets chirp. The basic equation found by prof. Dolbear is:

• `temperature = 50 + (chirps_per_min - 40) / 4`

However, Dolbear didn't specify the crucial information, such as the species of cricket or the number of the observations in the experiment. In our crickets chirping thermometer we are using this basic formula for the most common species in the US - field crickets, as it is working well enough, but Dolbear probably used the snowy white cricket to find the equation.

After the Dolbear's invention the interest in cricket sounds continued. Other scientists tried to check and develop the formula, and to cover specific species of the crickets:

• `temperature = 50 + (chirps_per_min - 92) / 4.7` - another formula for snowy tree cricket (Further Notes on Thermometer Crickets, by C.A. Bessey and E.A. Bessey, 1989)

• `temperature = 60 + (chirps_per_min - 19) / 3 ` - formula for common true katydid

The equations should work especially well over a range of about 55 to 72 °F and they are not used in the temperatures below 50 °F, as that's the threshold when the crickets stop singing.

If you prefer to use Celsius degrees, convert the units with our temperature converter or change them with simple click in this crickets chirping thermometer.

## Why the Dolbear's formula works

Have you noticed that reptiles and insects tend to be more lethargic on cold days? Crickets, as all cold-blooded animals, are dependent on the Arrhenius equation. It is the law describing the relationship between the rate of a chemical reaction and the surrounding temperature - we know intuitively that chemical reactions occur faster at higher temperatures (rotting fruits, butter rancidification, milk souring etc.), and the rule works in the same way for the living creatures. That's the exact mechanism behind crickets chirping thermometer: crickets' muscle contraction (essential to produce chirping sounds) is triggered by chemical reactions dependent on the temperature. So crickets will sing like crazy during the hot summer night, while in the cool morning they will be lethargic, apathetic, chirping in slow-pace.

If you want to listen to the crickets chirping in different temperatures, have a look at this website.

## Why do crickets chirp?

The chirps are not produced for kicks - those are crickets' love songs. The majority of chirps is made by male crickets, as most of the females don't have the necessary adaptations to make sounds. There are a few types of crickets sounds:

• calling song - attracts females and keeps other males away; it's a rather loud song as it needs to reach out all interested
• courting song - used to encourage female crickets to mate
• triumphal song - crickets sing it after a successful mating, to convince females to lay eggs
• aggressive song - when rivals are close

## How do crickets chirp?

The common myth is that crickets are producing the sound by rubbing their legs together - in fact, it's rather rubbing the wings than legs. Crickets are chirping by stridulation (from latin, strīdulus meaning: giving a shrill sound, creaking). The stridulatory organ is a big comb-like vein located on the fore wing. Also, there is a special structure called a scraper at the rear edge of that wing. To make a chirping sound, crickets rhythmically raise and lower their wings to make the scraper of one wing rasp the comb structure on the other. Do you understand now why cricket chirping is so similar to the sound of the fingernail across the comb teeth?

## Calibrate your cricket!

If you really want to use cricket chirps as an accurate temperature indicator, you should first calibrate your crickets against a thermometer placed near their singing area. Why? Because the difference may occur not only between the species but also between populations - the crickets on your field may sing differently than your friend's cricket thousands of miles away. As an example, let's take the snowy tree cricket, which is sometimes known as thermometer cricket - it chirps slower in the east of the US than in the west, probably because one other cricket species has a very similar song. As this other cricket species occurs only in the western US part, the western snowy tree crickets must have adapted to be heard and distinguished better, so they raised their frequency.

## How to stop crickets from chirping

If we are talking about keeping the cricket at home, there are a few of things you can try:

1. Light them up - illuminate the cage to mislead the cricket, as they are chirping mostly during the night.
2. Cool them down - put them in the basement or another cool place - below 70 °F chirping slows and diminishes in intensity.
3. End with sex segregation - the male crickets are chirping to woo the females - keeping them together can cut down on chirping sounds.

As you can see, a few solutions exist for pet animals. However, if you can't sleep in a tent because of the crickets chirping all around, we have bad news for you - it's not possible to stop them. Unless you can lower the temperature outside, lighten the night (or you're Bruce Almighty), you need to live with these sounds of nature. Try to relax, clear your mind and stop thinking about how to stop crickets from chirping (or simply use earplugs).

## Crickets chirping thermometer - how to use

Imagine a warm summer evening. You are laying in the grass next to the bonfire, birds are singing, crickets are chirping...

1. Prepare a watch, a phone or a timer. You will need it, as it's somewhat challenging to count two things at the same time. In the worst case, use the other person as a clock: one Mississippi, two Mississippi, three Mississippi...
2. Count the crickets chirp in a chosen period of time. The longer, the better. Repeat the counting a few times and take the average. Ideally, it should be one cricket chirping, not a cricket chorus.
3. Type the obtained value into our crickets chirping thermometer. Assume it's 60 chirps in half a minute, so 120 chirps/minute.
4. What is the temperature according to a cricket? Our crickets are showing 70 °F. Remember it's only the estimate as different species can react differently to the temperature.

But what if you don't have crickets around you, or they don't want to chirp? Well, that's a pity... Unfortunately, you need to use a standard thermometer or just rely on some forecast websites.

## Weather calculators

If you are keen on atmospheric studies and weather forecasts, have a look at our other weather calculators:

Hanna Pamuła, PhD candidate