The heart-rending barking of stray cats in the middle of the night is usually because they are in estrus or are calling for companions. This happens to female cats when they are in estrus, and it is the same for domestic cats, because female cats are more painful during estrus and need to howl to relieve it, and this kind of sound will also attract male cats or companions to come over, and then In addition, cats are nocturnal animals, so they are prone to this situation.