In the bigfoot community there is a faction which holds that the bigfoot and yeti are hybrids of humans and unknown apes. I don’t agree with them and I’ll tell you why.
In biology there is a phenomenon where different animals evolve features alike. An example would be the wings of bats and pterodactyls. The two are separated by millions of years, which the latter disappearing long before the former made their first appearance, Yet the latter had what has often been referred to as “bat-like” wings.
But the term convergent evolution really only applies when the two organisms are all that closely related, where bigfoot and humans are concerned the better term is parallel evolution. In that the two animals are closely related and they both evolve similar traits.
However, it would appear that those traits we think of as arising in humans first appeared in the common ancestor of both, only to disappear when the genes for them stopped being expressed—as happens from time to time.
This is when a gene or family of genes is “expressed”. That is, whatever the gene codes for is actually produced. But sometimes the gene is not expressed, so the trait remains hidden. In the case of the bipedal apes; bigfoot, humans, and yeti; the genes for bipedalism are expressed, while in the case of the arboreal apes; bonobos, chimps, gorillas, and orangutans; the genes either don’t exist or are not expressed.
My thinking is that bipedalism first appeared in an ancestor of the three bipedal apes, but was then lost in the ancestor of humans at the very least. Later in the course of evolutionary development bipedalism reappeared and among humans underwent specializations that didn’t occur among bigfoot or yeti.
The face and nose seen in all three animals are things I’m not clear about. They may be other examples of things that first appeared in our common ancestor, but were later lost in our more immediate ancestors only to reappear again later.
But, you get right down to it there really is no need for bigfoot or yeti to be any sort of hybrid with humans. As far as I can see all three animals are examples of parallel evolution caused by development in similar environments. And please note that at least where bigfoot is concerned, they don’t have the “refinements” that give us our uniquely human stride. In short, they don’t exactly walk the way we do.
That’s my take on the matter.