Why do you think female cats scream during mating with their male counterpart? Well, it is an all time thing for female cats to scream so loud, screech or become so aggressive during mating with tomcat or just after the do. When the male and female cats mate, they caterwaul. That is, they make yowling sound in heat and this can be quite loud. There's actually a reason for this uncommon attitude within the animal kingdom. Researchers have found out that this aggressive behaviour occur due to the tomcat’s organ having little barbs or spines on it. With this, when the tomcat inserts it's organ in the female cat, the spines lay flat, but when it is being withdrawn, the organ which has spines on it causes a raking action on the wall of the female cat’s organ. This causes a severe pain, and so the female cat reacts by attacking the male cat. As animal, probably it thought it's the male cats fault or it is so wise that on attacking, immediate withdrawal by the male will relief it of the pain. So, this leads to a question; Why was the tomcat’s organ designed to have spines? The reason is not farfetched. The female cats, a virgin one that have never mated do not ovulate. So, the pain that female cat goes through the first time it mates causes so much shock. It later initiates the ovulation cycle in 24 hours time or more. What happens afterward is that the female cat will be in intense heat for close to three days. Then, it might mate as quickly as thirty minutes after the first copulation. Another question is; What makes the male cat to bite the female cat on the neck during mating? The male cat does not also want to get injured due to the aggressiveness of its mating partner. And this leads to the holding by the neck, but this also adds to the anger of the female cat which makes it try to swipe the male to prevent its neck getting scruffy.