In terms of traits I discussed in this article, New Caledonian Crows are contenders for most complex non-human technology. Chimpanzees (and the other great apes) certainly make more varied tools, but New Caledonian Crows have tool technologies that show patterns of complexity and distribution that are more similar to the way human technology evolves. New Caledonian Crows have a tool that shows evidence of increased complexity over multiple generations. Still not conclusive though. In terms of language, we don't really understand dolphin language fully yet. So I don't want rule out the possibility that they can transfer information in a more efficient way than chimpanzees. Elephants aren't really contenders in any of these categories, although they do excel as tool makers. They are one of the few non-apes that make tools for non-food related reasons.