It is reported that a mature female rat breeds about once every 20 days or so, and one child can produce six or seven, and many can produce a dozen mice. A mouse can reach 1.5 to 2.5 months after birth. Mature and capable of reproduction. Interestingly, scientists have found that mice have the function of "family planning". When the total number of mice in an area is large, the mice will slow down their reproduction frequency, and when there are fewer mice or people kill rodents Later, they speed up reproduction and make mice multiply rapidly. What's the point of this text? ['Rats have a short lifespan and therefore a short life cycle.', 'Self-regulation of fertility in mice.', 'Rats have the amazing reproductive ability and are very harmful.', "Rats' reproductive ability depends on external environmental factors."]