why most animals have litters of babies when they give birth, but when humans give birth to twins or triplets, it’s considered rare?
In: Biology
Evolutionarily speaking, less sophisticated species are successful because of shear numbers. (Compare the hundreds and thousands of offspring frogs have with the scores that rabbits have with the dozens that cats / dogs have). Generally not only is it more “expensive” to grow a sophisticated animal, but also advanced social behaviours (parenting and community in homo sapiens) have meant that it’s more successful to have a small number of very well looked after children. This capability in turn has led to the evolutionary pressure in humans to tend to bear one child at a time – it gives them maximum growth advantage.
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