科学研究发现,人类以外的哺乳动物,如猪、狗、猫、牛、马等,它们的交配都受季节的严格制约,有明显的发情期或俗称“叫春”。也许正因为如此,它们的寿命大体符合目前提出的各种生物寿命理论,如不出现意外,都能活到它们应当活到的年限。可人类却偏偏是个例外——尽管也有一定的性欲规律,例如女性通过月经的来潮,可以计算出性欲比较旺盛的日子,但人类已无严格的发情期,性行为几乎可以随时发生。 Scientific studies have found that mammals other than humans, such as pigs, dogs, cats, cattle, horses, etc., are severely seasonally seasoned and have obvious estrus or colloquially called “spring.” Perhaps because of this, their lifespans are generally in line with the various theories of biological lifespans currently proposed, and can live to the extent they should live without any surprises. But human beings may have been the exception - although there are some laws of sexual desire, such as women through menstrual cramps, you can calculate the period of relatively strong libido, but humans have no strict estrus, sexual activity can occur almost at any time.