"The Comparative Anatomy of Eating", by Milton R. Mills, M.D.
CARNIVORE: Reduced to allow wide mouth gape
CARNIVORE: Angle not expanded
OMNIVORE: Angle not expanded
HERBIVORE: Expanded angle
HUMAN: Expanded angle
Jaw Joint Location
CARNIVORE: On same plane as molar teeth
OMNIVORE: On same plane as molar teeth
HERBIVORE: Above the plane of the molars
HUMAN: Above the plane of the molars
CARNIVORE: Shearing; minimal side-to-side motion
OMNIVORE: Shearing; minimal side-to-side
HERBIVORE: No shear; good side-to-side, front-to-back
HUMAN: No shear; good side-to-side, front-to-back
Major Jaw Muscles
HERBIVORE: Masseter and pterygoids
HUMAN: Masseter and pterygoids
Mouth Opening vs. Head Size
CARNIVORE: Short and pointed
OMNIVORE: Short and pointed
HERBIVORE: Broad, flattened and spade shaped
HUMAN: Broad, flattened and spade shaped
CARNIVORE: Long, sharp and curved
OMNIVORE: Long, sharp and curved
HERBIVORE: Dull and short or long (for defense), or none
HUMAN: Short and blunted
CARNIVORE: Sharp, jagged and blade shaped
OMNIVORE: Sharp blades and/or flattened
HERBIVORE: Flattened with cusps vs complex surface
HUMAN: Flattened with nodular cusps
The Natural Human Diet
According to biologists and anthropologists who study our anatomy and our evolutionary history, humans are herbivores who are not well suited to eating meat.
Unlike natural carnivores, we are physically and psychologically unable to rip animals limb from limb and eat and digest their raw flesh. Even cooked meat is likely to cause human beings, but not natural carnivores, to suffer from food poisoning, heart disease, and other ailments.
People who pride themselves on being part of the human hunter tradition should take a second look at the story of human evolution. Prehistoric evidence indicates that humans developed hunting skills relatively recently and that most of our short, meat-eating past was spent scavenging and eating almost anything in order to survive; even then, meat was a tiny part of our caloric intake.
Humans lack both the physical characteristics of carnivores and the instinct that drives them to kill animals and devour their raw carcasses. Ask yourself: When you see dead animals on the side of the road, are you tempted to stop for a snack? Does the sight of a dead bird make you salivate? Do you daydream about killing cows with your bare hands and eating them raw? If you answered "no" to all of these questions, congratulations—you're a normal human herbivore—like it or not. Humans were simply not designed to eat meat.
(statement from: http://www.goveg.com/naturalhumandiet.asp)