^^^^^^^ CB: Yes, and when a dog responds to its name or commands like "sit", "fetch" or when they point to game etc., they are using symbols too. This is due to very limited "enculturation" from living among humans. Same with the apes and chimps. But no other species develops symbol systems on its own outside of human contact. Also, I don't think the apes and chimps who learn small sets of vocabulary from humans don't teach it to each other. And I've never heard of them "talking" to each other. They only talk to humans.
Further all the trained apes and chimps have very limited vocabularies compared with humans to such an extent that the difference in quantity amounts to a difference in quality. In the wild, apes don't organize their societies based on symbol systems and language