What's interesting to me is the local variation of behavior -- onr group of gorillas will use such-and-such tools, while another will use different ones. One imagines this is because at some point in time some gorilla in the respective groups had the bright idea of using a pointy stick or a flat rock, other gorillas thought this idea was nifty, and they copied it and passed it on to their progeny -- resulting in, ta-da, transmission of ideas through generations, which, contra some people, does not require language.
I would speculate that this kind of thing can be observed in other species, including non-primates, as well, but is more obvious in the case of tool-users who lug big things about and use them in specific ways.
Anyway, higher primates are obviously capable of symbolic thinking, assuming that primate acquisition of sign language/communication through keystrokes is a reality (which I think it is in my layman's way).
I am not sure how accepted the notion is that dolphins communicate by firing sonar pictures at each other, but if it is true, that puts dolphin "language" quite definitely into the symbol-use category. ;)
(Post Scriptum. Symbol use is a small part of language.)
--- On Tue, 7/29/08, Charles A. Grimes <cgrimes at rawbw.com> wrote:
>
> For CD. I thought of that immediately when I read
> Dennis' post. The
> trouble is that cultural anthro has to define itself and so
> it draws
> the line between homo sapiens and other primates. But
> clearly many
> primate species have their own culture and use symbolic
> forms, mostly
> vocalizations and various mating behaviors, child rearing
> practices.