The original comment I was responding to in the article was concerning the ways humans were unique from animals. I'm not describing intelligence full stop, or claiming that animals are the basis for intelligence or reasoning. I'm not saying animals need to be like humans to be intelligent. My point is that the thing that makes humans unique from animals is our ability to reason, our cogitative powers.

They don't need to do it in the same way humans do; they don't do it in the same way humans do. In the absence of language, they have no way of expressing the depths of cogitation in the same way humans can.

In regards to your last question, I have found PMS Hacker a particularly compelling author in this area. He is a very good analytical philosopher. His works are peer-reviewed, and extensively researched and amply sourced. He's an established professional philosopher. He has also written extensively with M.R. Bennet, an established neuroscientist with many papers, a good book of theirs is: The Philosophical Foundations of Neuroscience (http://ca.wiley.com/WileyCDA/WileyTitle/productCd-140510838X...)

I'm not a professional scientist, I don't have access to papers. I have access to books.