There are, as I recall, about 5 other creatures with larger brains than humans including some dolphins. OTH, they don't have opposable thumbs so they can't really manipulate the world as humans can.
An interesting observation to share however it wasn’t my point- it is obvious elephants and whales have significantly larger brains than us and other great apes. I was simply saying it would seem we are the most intelligent lifeform on this planet. We do have the largest brain of all great apes however and it seems the largest brain size relative to body mass for all mammals.