Topic: The most intelligent nonhuman species...

[Dracho]

Any species who can't master fire isn't going far up the evolutionary ladder..  Fire is a prerequisite for civilization, which pretty much ensure dolphins, whales, and arthropods aren't going anywhere fast, unless they come back onto land.  

[Stormbringer]

Only a technological species. The critters in the sea have no need for it. Thier environment is rich enough in stimuli and challenges to develop their intelligence. Plus, they do have access to fire in a limited fashion, The volcanic rifts, smokers and so forth.