When is a female cat in season?

When a female cat is ‘in season’ she is ready to mate (in heat) and this readiness is dependent upon the season (i.e. winter, spring, summer and fall). Queens (intact females) vary at which age they first go into heat. Puberty in male and female cats usually starts at between 6-9 months. However, cats of the Siamese family may have their first heat at 5 months.

Cat in heat. Photo: O’Meara – Pet Informed. I modified the image slightly to make it a bit different.

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Cats have repeated heat cycles (reproductive cycles) over the year. This is described as ‘polyestrous’. ‘Poly’ means more or much and ‘estrous’ means the period of heat. As the seasons (the time of year) affects the process cats are called ‘seasonally polyestrous’. The seasons affect the amount of daylight that cats experience.

The female’s reproductive cycle is most active when the hours of daylight increase. As the daylight hours decrease the reproductive cycle winds down.

Increased daylight stimulates her pituitary gland to produce ‘follicle stimulating hormone (FSH). In turn FSH induces her ovaries to manufacture eggs and the female hormone oestrogen.

The oestrogen is released in her urine which attracts males who use their vomeronasal organ to detect it. If he detects the scent he’ll focus on finding the female and be ready to fight over her if necessary.

At puberty the female’s eggs are waiting in her ovaries. The ovaries are released after mating has taken place. The ovulation is triggered by the intense pain she experiences as the male’s barbed penis is withdrawn, raking the sides her her vagina.

I hope this answers the question in the title.

Sources: Myself, Dr Bruce Fogle and Cat Owner’s Home Veterinary Handbook.

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