If two races of human beings can mate, what keeps us from procreating with animals

There are obvious differences between races, but we can almost flawlessly mingle with each other, save for genetic disorders, which are hereditary. I don't see why humans, in this case, would be unable to breed with animals?

I understand your question. It is not trolling.


Different races were essentially formed because of isolation of human populations in different environments and different regions etc.

Now this led to changes in particular features over time, but there was simply not enough time for the races to diverge such that they were distinct species. The definition of a species are organisms where they can generally reproduce and produce viable offspring (or theoretically are able to). Theoretically, given enough time the races would have branched off into different species, but once again there wasn't enough time isolated from each other - such changes take too long. Also, knowing the human race, they would not stay isolated for too long, because they travel a lot and are able to expose themselves to many environments around the world, and hence finding the other populations wouldn't be too hard. Nowadays, it is extremely hard for human divergence to occur because of transport and the idea that many races are mixed together in a multicultural system.

With other animals, they diverged from humans with a much longer time span, and did not mate with them. Over time, they were unable to mate with humans.

When we look at humans, they are under the species (Homo) sapiens. All races are in this H. sapiens category, hence they are under the same species and can mate to produce viable offspring.

What I find interesting is that some animals today who live on different islands, can mate with the birds (same type of bird) on the islands adjacent to them, but not from ones on islands further away.

Here is some food for thought:

So as an example, using these numbers: