Replies:
This has to do with survival of the fittest. Organisms that give no parental
care, i.e. fish, frogs, have hundreds of offspring at a time. They abandon
their eggs and the probability that only a few will survive to reproduce is
great. Humans usually have only one child at a time and take very good care
of them for a long time. Other mammals are closer to us, but they don't take
care of their young for as long as we do. So they have more to insure that
at least some will survive to reproduce.
vanhoeck
The number of offspring is directly related to niche of the animal and the
availablity of the mammals food supply. The higher the mammal is in the food
chain, the smaller the number of offspring at a given time. Mammals sucha as
rodents have to produce large numbers for most will not survive to reproduction
age due to predators, so you have larger litters.
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