Why did no one understand how Hans could do such remarkable and unusual feats?

Animals

Explanation:

The number faculty is profoundly rooted in our biological ancestry, not dependent on our ability to use words. In view of the multitude of contexts in which we humans use numerical knowledge, life without numbers is inconceivable.

It turns out that processing numbers provide a major survival advantage, which is why this behavioural characteristic is present in many animal populations. Several research studying animals in their ecological settings indicate that the representation of numbers increases the ability of animals to access food sources, hunt prey, escape predation, navigate their habitat, and persist in social interactions.

Long description. This is the best I could do. Hope it helps. I did not quite understand your question. Sorry.

where are the multiple choice answers?