Clarification between animal and man

One of the constant questions that I have had since this class began is how animals fit into this picture of reasoning and how they differ from humans; even though we are animals too. Originally I would have said that animals do have practical judgement and that a humans viewpoint of what reasoning is goes against nature. But after further review it seems that human reasoning is just more in-depeth and therefore not against nature but different because of our use of actions instead of just sense stimuli.
With that being said I still can't shake the suspicion that some animals may reason much more than we expect. Because in the end reasoning can not be observed and it is only by observation and communication that we try to differentiate between what is simply reaction to sensation and what is reasoning.