Communication in many of its facets is not limited to humans, or even to primates. Every information exchange between living organisms — i.e. transmission of signals involving a living sender and receiver - can be considered a form of communication. Thus, there is the broad field of animal communication, which encompasses most of the issues in ethology. On a more basic level, there is cell signaling, cellular communication*, and chemical communication between primitive organisms like bacteria, and within the plant and fungal kingdoms. All of these communication processes are sign-mediated interactions with a great variety of distinct coordinations.
*This link was inspired by Jorge Luis Borges, who used in his books real and imagined literary references derived from an infinitely imaginary library.
"If Jorge Luis Borges had been a computer scientist, he probably would have invented hypertext and the World Wide Web. Instead, being a librarian and one of the world's most widely read people, he became the leading practitioner of a densely layered imaginistic writing style that has been imitated throughout this century. Borges's stories are redolent with an intelligence, wealth of invention, and a tight, almost mathematically formal style that challenge with mysteries and paradoxes revealed only slowly after several readings. Highly recommended to anyone who wants their imagination and intellect to be aswarm with philosophical plots, compelling conundrums, and a wealth of real and imagined literary references derived from an infinitely imaginary library."