From Barbara Ehrenreich’s “The Animal Cure”, from issue 19 of The Baffler, on spiritual encounters with animals, as reprinted in Harper’s magazine, June 2012:
[p. 14] We may not worship golden calves or offer human sacrifices to jaguar gods, but implicit in much of the new attention to animals is the commendably liberal idea that they are not – intellectually, or morally – all that different from humans. After all, they can use simple tools; they can be altruistic; they can create what they seem to regard as works of art; they can reason and remember; they can fall int what looks like depression. Language is widespread in the nonhuman world, and not only among birds, dolphins, and whales. Recent research has found that American prairie dogs, which are closely related to squirrels, can issue calls informing one another about what kinds of creatures might be approaching.
This is the widespread use of language to mean ‘communication’, in a very broad sense of communication. Not to disparage the abilities of animals, but systems of communication among animals are different from (not necessarily inferior to) human languages in a great many ways, so that it’s profoundly misleading to treat all these things as somehow the same.
Consider insects. Insects display quite a range of communication systems that rely on acoustic or visual cues — think of crickets and fireflies — and a stunning array of communication schemes using chemical cues (on which there’s quite a considerable literature).
And also for plants. Here’s a brief survey for the lay person:
What is chemical communication in plants ? Plants relay on chemical signals to communicate with each other and themselves. Some of these chemicals are volatile (known as volatile organic compounds) and can be released from leaves, fruits, and flowers. VOCs play various roles in plant development, survival, and gene expression.
What sends and receives these signals? Three main type of plant-to plant signaling are known: interspecific, with plants of other species; intraspecific, with plants of the same species; and autosignaling, within the same plant, either internally or exernally. For example, bean plant leaves, infested with spider mites release volatiles that increase the resistance of uninfested bean plants nearby.
Plants also can communicate with insects. For example, corn, cotton, and tobacco under attack by caterpillars emit volatiles that simultaneously attract parasitic wasps to eat the caterpillers and discourage other worms and moths from laying their eggs on the platns.
What type of chemicals are used? A variety of different compounds, including fatty acid derivatives and ethylene have been implicated in plant communication. Transgenic tobacco plants engineered to be insensitive to ethylene over grow their neighbours, while wild-type plants do not, which suggests a role for ethylene in controlling social behaviour. (link)
Again, there’s a considerable technical literature.
That’s just “higher” plants. Let’s talk slime molds (protists, essentially amoebas in a bag), which are famous for their communicative abilities, even to the point that some writers metaphorize their behaviors as intelligent. So, in the NYT Sunday Review, Andrew Adamatzky and Andrew Ilachinski applaud “The Wisdom of Slime”, reviewing some research on the way slime molds can use chemical communication to reproduce human networks, including the major aspects of the US interstate highway system (and of the Tokyo rail system, etc.), by optimizing connections. If you want to design a good transportation system, hire some slime molds!
Still, I’d be most reluctant to say that slime molds, bean plants, or even fruitflies are not — intellectually, emotionally, or morally — all that different from humans.