I've also pondered on this as an atheist argument. If praise, worship and obedience are so important to our God(s,) which they seem to be- why isn't there more evidence of a dinosaur version of Jesus, Moses, Muhammad type figure? Dinosaurs were here for a massive 165 million years compared to our measley 6 million. Why even get rid of the dinosaurs to begin with? Because God suddenly wanted a bunch of 'groupies' to adore them? (Assuming that animals don't or can't.)
I'd agree with others that humans do appear to have a particularly strong capacity for self awareness and an enquisitive mind for trying to figure out our place in this world. I suspect it's one thing leading to another though. Having enquisitive minds that learnt how to use tools, that were accutely aware of death and that figured out we could exploit our surroundings and other creatures gave us an evolutionary edge- no doubt. Once we'd tamed or slaughtered the things that posed a threat to us. Once we'd figured out ways to spend less time simply surviving, there must have been more time to set our minds on other things. Philosophy, writing, reading, telling stories. I suspect most animals are so worried about just remaining alive, there's less time to contemplate other stuff.
Funnily enough though, a friend of mine once bought a ceramic frog model for the garden. They noticed that all the real frogs would gather around it. Like it was their God.
Some animals do seem to participate in rituals which suggest a sort of respect and reverence. Elephants will cover their dead with leaves and branches. Maybe that isn't exactly spiritual but, it's interesting. Why would they do that? Do they want to try to prevent them becoming carrion? It does seem like a form of protection. They will also study the bones of dead elephants. That clearly shows a fascination/ understanding and a respect for one another- dead or alive, if not for a God.
I tend to agree though- that religion and God could well be man-made . There's that brilliant quote:
"God created man in his own image. And man, being a gentleman, returned the favor." Henri Rousseau