Why don't other animals have religion, or do they?

[Mnementh]

That's a pretty interesting question. I know, this question is probably thought of a way to make atheists uncomfortable. But as I'm interested in both evolution and the working of the brain/intellect, this is a really amazing question. And I personally think most progress in science comes not from answering questions, but from asking new and interesting questions.

To the topic at hand: I fear the science has no answer ... yet. If we look at the human evolution, we know pretty much about the evolution of the human body, but near to nothing about the evolution of the human mind. There are some interesting things. Early humans first didn't made cave paintings. But at some point they not only started it - fast many human settlements had started to paint into caves. It seems, that they were already able to it. But nobody had the idea. As the first one started to make a painting, this idea got fast around the human population. Could something similar have happened with the religion? Maybe, but I'm not sure. What really happened here is hard to guess.

I think (my theory) that some animals have religions - simple religions with obviously no written history and rules and probably not as institutionalized as human religions. But they may have one. The factors I think are important for a religion to develop are:
a) a social society
b) some form of more advanced communication
c) the ability to learn things from elders
d) a long-term memory
Some of the animals (dolphins, apes, maybe more) have these factors. But we didn't really decode their language. Maybe if we in some future decode the dolphin-language, we learn that they discuss about the great rains that created the world.