We are out-numbered by many orders of magnitude by a number of different animals:
Which life form dominates Earth? http://www.bbc.com/earth/story/20150211-whats-the-most-domin...
This strange, glowing fish is more abundant than rats, chickens, and humans combined https://www.businessinsider.com/bristlemouth-fish-is-the-mos...
Along With Humans, Who Else Is In The 7 Billion Club? https://www.npr.org/sections/thetwo-way/2011/11/03/141946751...
On the other hand, Sapiens has a good quote about there being 2 (at least ?) orders of magnitude more domesticated dogs than wolves in the world. Ditto for pigs and wild hogs, or cattle and comparable wild herbivores.
It has many other pretty shocking statistics about large cats, elephants, etc. The world today is simply much more suited to a dog's way of being than a wolves'.
To put it more starkly, wolves will likely be extinct long before dogs are, because of their different relationship to humans.
But of course ants and other species don't compete for the same resources as humans, and are complementary many ways.
Similarly, "the computer is a bicycle for the mind."
For reference, a billion years ago, there were no animals or plants yet.
Given that, maybe there are a lot of species that really weren't too far off from human level intellligence, but we just got there first?
Fire is related to agriculture but maybe not essential. It could be some other kind of chemical reaction that occurs outside the body.
It's hard to imagine how descendants of orcas could create agriculture in the ocean, but not impossible. I mean humans have domesticated fish, shrimp, mollusks, etc. for farming. And probably some marine plants.
It does seem like shallow water is probably the best bet, but maybe that's my lack of imagination.
I wonder if one of them would achieve human-like intelligence if they evolved for a billion more years. I would bet on it.
And then they would probably multiply without control, and kill off all their competitors.
On land, humans have done that. Although elephants are very intelligent, we're the smarter than them and outnumber them and all other animals by a large margin. We live on nearly every part of the earth.
It would be interesting/weird if the sea filled up with one large, intelligent animal that lived everywhere.