In my experience, all species of mammals include a range of individuals whose intelligence ranges from 'barely able to survive' through to genius (or near to it). The level of intelligence is somewhat connected to the body they are expressing through - since a cow can't use the internet and sit and study quantum physics, for example - and so they are limited in terms of what they can learn and how much they can expand mentally.
also doubt the intelligence of humanity.
exactly - there are some very smart humans and some very limited humans, it's the same even with cows.