Why there isn’t variety of human beings like different species of cows, bats and every other mammals?
In: Biology
One thing to think about is if you’re considering all bats as the same “type” of animal then really humans are the same “type” (primate) as lots of other species like chimps, gorillas, even monkeys. In fact we are much more closely related to some other primates like chimps than many bats are to each other.
We will never know exactly why, we can only hypothesize. We may have outbred and outcompeted the other species. We are certain that we interbred with some of them, maybe they never went anywhere and are still with us.
One particularly interesting hypothesis is that modern humans have a shorter period of breastfeeding than earlier hominids, and generally breastfeeding supresses reproduction. Thus we bear more children. This is offset by a higher need for calories and protein for the big brains and big brood, which we have offset by cooking food. We can create calories out of something that our ancestors could not even chew. Our kitchens are essentially part of our stomachs, some of our distant ancestors probably spent a significant portion of each day chewing tough foods, we can gulp them down after cooking and move on to other things, like hunting for more food. We also retain more body fat than chimps and possibly early hominids (we don’t have anything but bones from those ancestors) which allows us to nourish the big brains through hard times, and bedevils us today when few people starve. Once again this is a hypothesis, we will never prove it until we can observe Australopithecus and the like directly. Wait for the time machine.
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