How long does the estrous cycle occur?

The estrous cycle varies among species but typically lasts about 21 days in many mammals, such as dogs and cats. In some animals, like cows and horses, it can range from 18 to 24 days. The cycle includes several stages: proestrus, estrus, metestrus, and diestrus, during which hormonal changes prepare the body for potential reproduction. However, the duration and characteristics of the cycle can differ significantly across different species.