Do you have some evidence of that? And even if it's true, is it the only thing that's unique to humans?
Indeed, I suspect the interesting part of "believe in god" in terms of intelligence is probably "construct narratives". Assigning a high probability to those narratives reflecting reality (i.e. believing) seems like an aside to the main complexity involved.
>"The anthropologists got it wrong when they named our species Homo sapiens ('wise man'). In any case it's an arrogant and bigheaded thing to say, wisdom being one of our least evident features. In reality, we are Pan narrans, the storytelling chimpanzee." - Terry Pratchett, The Science of Discworld II: The Globe