What I find interesting about life, is that there is only one breed of human on this planet. And maybe breed isn't the right word, but take dogs for example. If dogs were like us, there might be only labradors. Sure there would still be different types of labs, there just wouldn't be any mastiffs, beagles, etc. We were taught growing up that homo sapiens and neanderthals didn't occupy the earth at the same time, but now we know that's not true, and that there was inter breeding between them. Why did neanderthals, denisovans and maybe others, die out, yet we survived?