Why does the cat go into heat every month? - briefly
The cat is an induced ovulator, meaning it only releases eggs (ovulates) in response to mating or stimulation from a male cat. If not bred, the cycle repeats every 14-21 days, leading to monthly heat cycles.
Why does the cat go into heat every month? - in detail
Cats are polyestrous animals, which means they experience multiple estrus cycles during their breeding season. This is in contrast to many other mammals that are monoestrous, such as dogs, which have only one estrus cycle per year. The cat's reproductive system is designed to support frequent mating opportunities and the production of offspring throughout the spring and summer months.
The feline heat cycle is regulated by several factors, including day length, which increases during the spring and summer. This change in daylight triggers the release of hormones from the pituitary gland in the brain, signaling the ovaries to produce more estrogen. The increase in estrogen levels stimulates the growth and development of follicles within the ovaries, which contain immature eggs. As these follicles mature, they secrete even more estrogen, creating a positive feedback loop that amplifies the hormonal signals.
During this phase, known as proestrus, the cat exhibits behavioral changes such as increased vocalization, restlessness, and rubbing against objects or people to mark her territory with pheromones. These behaviors are designed to attract potential mates and signal that she is ready for mating. The proestrus phase typically lasts about 1-2 days but can vary depending on the individual cat's reproductive health and age.
Once the follicles have matured, they release a surge of luteinizing hormone (LH) from the pituitary gland. This LH surge triggers ovulation, during which the eggs are released from the follicles into the fallopian tubes. Ovulation in cats is induced by mating, meaning that the physical act of mating stimulates the release of hormones that cause ovulation to occur. This process ensures that fertilization can take place immediately after mating, maximizing the chances of successful conception.
Following ovulation, the remaining follicular tissue in the ovaries transforms into structures called corpora lutea. These corpora lutea secrete progesterone, which helps to prepare the uterus for implantation of a fertilized egg and supports pregnancy if conception occurs. If the cat does not become pregnant during her heat cycle, the corpora lutea will eventually regress, causing progesterone levels to decline, and the estrus cycle will begin again with the next surge in daylight hours.
The entire estrus cycle in cats, from the onset of proestrus to the regression of the corpora lutea, typically lasts about 4-7 days. However, if a cat is not bred during her heat cycle, she will go back into heat within 10-14 days after the previous cycle has ended. This short interval between cycles allows cats multiple opportunities to mate and become pregnant throughout their breeding season.
In summary, the monthly heat cycles in cats are driven by changes in daylight, which trigger hormonal responses that prepare the reproductive system for mating and potential pregnancy. The frequent estrus cycles in cats reflect their evolutionary adaptation to maximize reproductive success during the optimal breeding months of the year.