eli5 If it’s suspected that early humans interbred with other species of humans, why would they be considered different species since the offspring were obviously fertile?

Question

eli5 If it’s suspected that early humans interbred with other species of humans, why would they be considered different species since the offspring were obviously fertile?

In: 54

Answer 1

Think about dogs, wolves, and coyotes. Different species, because they would not interbreed without significant interference in their natural patterns.

And yet in some areas nearly all the coyotes show some degree of dog or wolf ancestry, because in a disturbed ecosystem the lines tend to blur.

And even in clean environments, some species will tend to hybridize. If there are two closely related species, one adapted for the hills and one adapted for river bottoms, maybe they will grade into each other with hybridization. Maybe the hybrids will even be the best adapted for the foothills.

Remember, a species is defined by reproductive isolation, not by reproductive impossibility.