In heat (literally)

The Greek author Claudius Aelianus (c. 170–235) wrote De Natura Animalium, “On the Nature of Animals,” which gives some insights into what the ancients knew (or thought they knew) about beasts.

He observed that a female cat in heat was “extremely lustful,” but that she did not enjoy the actual mating, since the male cat’s semen was “extremely hot and fiery, and burns the female.” Not true, but certainly a colorful explanation as to why female cats do seem to find mating very painful.