What exactly is sexual desire? To put it simply, it is a person’s desire and desire for sex. Not only humans, but also animals have sexual desire, which is what we often call “heat”. However, the estrus period of animals is relatively short, such as the giant panda, the national treasure of China, which only comes into estrus in March and April every year. Humans and their closest relatives, chimpanzees, are not restricted by estrus and can have sex anytime and anywhere. Of course, this ability is not innate, but the result of the evolution of species from low to high.