"The reason the theory of evolution is so controversial is that it is the... main scientific prop---for scientific naturalism. Students first learn that "evolution is a fact," and then they gradually learn more and more about what that "fact" means. It means that all living things are the product of mindless material forces such as chemical laws, natural selection, and random variation. So God is totally out of the picture, and humans (like everything else) are the accidental product of a purposeless universe. Do you wonder why a lot of people suspect that these claims go far beyond the available evidence?"
To put it another way: I try to hang out with animals to the fullest extent possible. Mostly I just enjoy their company -- however brief, as usually seems the case when it comes to wildlife.
In dealing with domestic animals however -- dogs, cats, and horses form my experiential base -- it has been my experience that they react/respond, not to language, but to signals. Some of these signals may be verbal. Some may be physical cues.
The point is: Reaction to a signal does not necessarily prima facie demonstrate advanced cognitive abilities, let alone language interpretation skills.
Thus it seems to me that "reason," as you appear to describe it, cannot be a "body of knowledge." Rather, I'd say it's the preeminent tool for the qualification of what can pass for knowledge, as mediated by logic and experience.
Based on my experience, in general, animals do not exactly excel in the kind of intellectual operation that depends on language for its intelligible communication.
So if you were to tell me that there really isn't any real distinction of consequence as between humans and other animals (which is the "reasonable" conclusion to draw from Darwinist theory), then I'd have to say:
Show me: I'm just dying to see your evidence. Hopefully, what passes for evidence with you will not be wholly speculative, but would take actual life observation and experience into account....