[Volsung]

PA certainly has a point about being the only intelligent species we know of, but allow me to post a few bulletins.

1. Humans are physically some of the weakest animals there are, incapable of surviving without tools or weapons in the wild. What then is our defense mechanism? No matter how you say it, the bottom line is that we are able to reason abstractly. We can put meaning into meaningless things, creating weapons, homes etc. Our defense strategy is culture. We are the only species to have that.

2. Unfortunately the ability for language is hindered without the ability for abstract thought. I don't know about the Cat example above, but many apes have predetermined soundsets for communication. This means that the same species ape in africa and europe could warn each other about a snake, but neither could make a sound to represent a plane. Humans again are the only animals known to have linguistic variety.

3.There's no way of knowing for sure what the parrot could understand. If it could speak knowledgeably in a human tongue there's no telling whether it's learned a format to speak in or whether it's truly gone a step higher on the evolutionary ladder. (By higher I simply mean more complicated or sophisticated) No matter which is the truth, it still implies that it is the physical limitations of the vocal chords that hinders human to animal communication.

4. No matter that all the above put humans at the top of an evolutionary list, it seems asinine to believe that other creatures can't reach the same pinnacle. Many animals have some of the characteristics (Raccoons-opposable thumbs; Bears can walk erect; parrots and ravens have similair vocal abilities) yet none have the ability to reason abstractly. Still, Time and evolution march on. It is inevitable that another species will emerge as a recognizable intelligent life form.

5. A final note: it's probable that animals can reason abstractly to a certain degree. In fact, I'm pretty sure there's evidence of such. (Would the sign-language gorilla indicate this? I'm not sure.) Anyway, No animal has all these characteristics combined. When I see a squirrel in a loincloth, I will know the evolution has come.

Or should this have been in off-topic?

Edit: Note that I said pinnacle in No. 4. This is wrong. There's no reason to believe humans are at the top of the evolutionary ladder. In fact, seeing a top to evolution seems counter-productive. That was pure egocentrism in regards to humans. Sorry.