David's+answer

While some people have said that failures to domesticate animals in certain regions of the world is a result of cultural difference, Jared Diamond counters with a claim that geographical luck and animal behavior are the two causes of it all. Diamond instead states that there are only a handful of large terrestrial mammals that are truly capable of domestication, and it is mere luck that most of them were concentrated in small areas, with most hailing from the Fertile Crescent. According to Jared Diamond, the ones that could not and cannot be domesticated have one or more of the following flaws: demanding diet, slow growth rate, breeding issues, nasty disposition, tendency to panic, and inappropriate social structure.

Because of sheer luck, most large land mammals that can be domesticated were in select places, and the ones that are not capable of domestication have been and continue to be incapable of domestication. This has been shown by more modern attempts. Essentially, if something was not domestication-capable before, it is not now. A good example of this is the eland, which has an improper social structure, not forming any close ties, and probably not following a leader.