Did you know that rats are one of the most sexually active creatures in the planet? In one year alone, a pair of mating rats can have at least 5 litters and each litter would have up to 15 baby rats or pups. When the pups reach 5 weeks old, they themselves become fertile and can have their own litter. So theoretically, it is possible for a pair of rat to produce thousands or millions of descendants in one year. It is pretty scary.
But why do rats have high breeding rate? Well, this is because it is necessary for the survival of their species. Very understandable because rats have plenty of predators like cats, snakes, weasels, owls, hawks and many other predators. In fact, it is rare to see a rat that goes beyond its 2nd birthday. Moreover, the mortality rate of rats during their first few weeks is high. Mortality rates can even reach up to 95%.
Now imagine if rats do not have predators and do not have high mortality rates. Our planet would be overrun by rats within just a few years. Various diseases would plague humanity. Vegetation in the planet would be annihilated because rats would eat almost anything. They might even feed on other animals and might cause the extinction of certain species. Even the rat removal would be useless. In the end, the proud human race would be obliterated on the face of the planet and rats would be the sole survivor of this planet. Fortunately for us, this apocalyptic scenario is far from reality.