Aren’t bee waggles, ant pheromones, dogs barking and animal mating calls naturally occurring codes?
These things are all codes, but animals and insects exhibit some level of intelligence. Animals and insects come from other animals and insects so they don’t qualify. We don’t know the origin of DNA or animals or insects, so these examples don’t count as evidence for non-intelligent origin of DNA. Any candidate for a naturally occurring code must be derived independently of all known life forms and human designs.