Are animals as intelligent as human? What language does to us is to be able to pass on knowledge to generations, knowledge can be accumulated. Animals may be able to pass on simple concept to next generation, they won't be able to accumulate knowledge without language and writing.
As a response to leftyted, erispoe's point neither depends on nor implies that animals are as intelligent as humans, it is simply bringing up a counter-example: what appears to be knowledge in animals lacking language.
Of course, you could always attempt to define knowledge such that it is purely verbal, or alternatively define whatever is going on in the brain of an animal to be language, but is either approach useful? In common usage, we recognise, as knowledge, various things that cannot be communicated by language, such as knowing how to ride a unicycle on a tightrope (I doubt you can learn it just from a book) and the infamous qualia which supposedly prove that the mind is dualistic. And what about the knowledge of how to use language? How does that get bootstrapped?
The knowledge of riding a unicycle on a tightrope does not give you the ability to ride a unicycle on a tightrope. Yes, you have to learn it through experiencing it, because you need to map it to your motors. Animal has instincts, they are able to trace water, for example, without teaching. It is also knowledge, but for our discussion, knowledge is what we obtained after birth, not something encoded in our DNA. This knowledge is stored in the format of language. Apparently some believes that that language is part of our DNA. That's why you can have Tazan, but not an animal can speak human language even if a human raise it since it was born because language cannot be learnt without support in code in DNA.
If we define knowledge that way, leftyted's original claim (knowledge is language) becomes true by definition.
This can lead to some confusion. In Frank Jackson's Knowledge Argument[1], dualists say that qualia are knowledge, knowledge is language, and so if Mary could not learn qualia by studying science, then materialism is false. This argument trades on being inconsistent over what it means to have knowledge of something.
In important ways yes, and in important ways no. Yes: can deal with dynamic spatial environments, can act towards a goal (intentionality), some almost certainly can plan how to reache these goals. No: Use of symbols and recursive language.
