Carnivorous animals most resemble man in their digestive apparatus.
Experiments and Observations on the Gastric Juice and the Physiology of Digestion
Arguments from analogy may be very plausible, and are certainly very allowable, when the subject presents no other mode ; but they are not conclusive. We cannot judge of the mode of digestion in the human stomach by that of animals, particularly the granivorous and ruminating animals. Carnivorous animals most resemble man in their digestive apparatus. One thing is certain, and it is capable of demonstration in the stomach of the subject of these experiments, that old and new food, if they are in the same state of comminution, are readily and speedily mixed in the stomach.
Dr. William Beaumont