The fact is that camels are far more intelligent than dolphins. They are so much brighter that they soon realised that the most prudent thing any intelligent animal can do, if it would prefer its descendants not to spend a lot of time on a slab with electrodes clamped to their brains or sticking mines on the bottom of ships or being patronized rigid by zoologists, is to make bloody certain humans don't find out about it. So they long ago plumped for a lifestyle that, in return for a certain amount of porterage and being prodded with sticks, allowed them adequate food and grooming and the chance to spit in a human's eye and get away with it.