The Monkeys with Grammar
Campbell’s monkeys add suffixes to alarm calls to indicate specific threats, and Diana monkeys tune in for their own benefit
Several years ago, researchers discovered that wild Campbell’s monkeys can alter the meaning of their “krak,” “hok” and “boom” calls by adding suffixes. Just as adding the suffix "-dom" to the word "king" creates "kingdom," the monkey's suffixes help indicate specific threats. “Krak” means a leopard is present, for example, while “krak-oo” indicates unspecified danger, such as a falling branch or another troop of monkeys encroaching on the caller’s territory.
It makes me wonder how much longer we'll be holding onto the claim that humans are the only ones with language. :)
Oh my gaawd!!! Everyone, take a look at this article if you get the chance. It's amazing what Koko has learned! And if you get to the last section, "Koko's Pets", you will both laugh and cry at the touching story of Koko's pet kitten, All-Ball, whom she named herself and chose to adopt.
Koko with All-Ball
As far as I know, that's not the claim. For all we know, the are many complex signal systems in the animal world (nightingales even seem to learn local "dialect" to attract females, having moved to a differnt territory). However, there are good reasons to doubt these can be called languages as we understand "language".
When we are talking about human languages, we mean (at the very least) that the words are arbitrary and the sentences have syntax (i.e. you do not just throw in all the words in random order). I don't know how essential these two are, but, well, it does seem reasonable that a flexible language should prescribe some rules about the way you combine the words.
So, of course, any evidence that animals have a notion of syntax makes a huge difference.