This is not a good comparison, because the brain doesn't only do "being smart" - it has to do things like innervate muscle and other tissue through the body, elephants will require more neurons given their larger size, just to be able to *walk*

You're comparing completely different training data, harness overhead, and cost function. You're also comparing brains, which aren't really related to this discussion at all.

But, it depends on what you're measuring. By spatial/navigational memory, yes, elephants are far far better. Reasoning, no. It would be interesting to see what an elephant or whale eugenics program could result in, since humans have that pesky (or maybe instrumental?) birth canal problem.