Humans Are Herbivores

and ecologically defined like all creatures

human anatomy and physiology

on March 6, 2012



Dr. T. Colin Campbell, professor emeritus at Cornell University and author of The China Study, explains that in fact, we only recently (historically speaking) began eating meat, and that the inclusion of meat in our diet came well after we became who we are today. He explains that "the birth of agriculture only started about 10,000 years ago at a time when it became considerably more convenient to herd animals. This is not nearly as long as the time [that] fashioned our basic biochemical functionality (at least tens of millions of years) and which functionality depends on the nutrient composition of plant-based foods."

Our faculties are co-evolved to allow certain niche behaviors and not others.

 “Early humans simply couldn’t eat meat.” Donna Hart, Ph.D. & Robert Sussman, Ph.D. Man the Hunted: Primates, Predators, and Human Evolution

Respecting our co-evolved faculties enables ecology to work for us and enables us to support the general ecology.

Comparative Anatomy of Eating Chart by Milton Mills, MD.

Misfit? Mouse Pad Facial Muscles
CARNIVORE: Reduced to allow wide mouth gape
HERBIVORE: Well-developed
HUMAN: Well-developed

Jaw Type
CARNIVORE: Angle not expanded
HERBIVORE: Expanded angle
OMNIVORE: Angle not expanded
HUMAN: Expanded angle

Jaw Joint Location
CARNIVORE: On same plane as molar teeth
HERBIVORE: Above the plane of the molars
OMNIVORE: On same plane as molar teeth
HUMAN: Above the plane of the molars

Jaw Motion
CARNIVORE: Shearing; minimal side-to-side motion
HERBIVORE: No shear; good side-to-side, front-to-back
OMNIVORE: Shearing; minimal side-to-side
HUMAN: No shear; good side-to-side, front-to-back

Major Jaw Muscles
CARNIVORE: Temporalis
HERBIVORE: Masseter and pterygoids
OMNIVORE: Temporalis
HUMAN: Masseter and pterygoids

Mouth Opening vs. Head Size
HUMAN: Small

Teeth: Incisors
CARNIVORE: Short and pointed
HERBIVORE: Broad, flattened and spade shaped
OMNIVORE: Short and pointed
HUMAN: Broad, flattened and spade shaped

Teeth: Canines
CARNIVORE: Long, sharp and curved
HERBIVORE: Dull and short or long (for defense), or none
OMNIVORE: Long, sharp and curved
HUMAN: Short and blunted

Teeth: Molars
CARNIVORE: Sharp, jagged and blade shaped
HERBIVORE: Flattened with cusps vs complex surface
OMNIVORE: Sharp blades and/or flattened
HUMAN: Flattened with nodular cusps

CARNIVORE: None; swallows food whole
HERBIVORE: Extensive chewing necessary
OMNIVORE: Swallows food whole and/or simple crushing
HUMAN: Extensive chewing necessary

CARNIVORE: No digestive enzymes
HERBIVORE: Carbohydrate digesting enzymes
OMNIVORE: No digestive enzymes
HUMAN: Carbohydrate digesting enzymes

Stomach Type
HERBIVORE: Simple or multiple chambers
HUMAN: Simple

Stomach Acidity
CARNIVORE: Less than or equal to pH 1 with food in stomach
HERBIVORE: pH 4 to 5 with food in stomach
OMNIVORE: Less than or equal to pH 1 with food in stomach
HUMAN: pH 4 to 5 with food in stomach

Stomach Capacity
CARNIVORE: 60% to 70% of total volume of digestive tract
HERBIVORE: Less than 30% of total volume of digestive tract
OMNIVORE: 60% to 70% of total volume of digestive tract
HUMAN: 21% to 27% of total volume of digestive tract

Length of Small Intestine
CARNIVORE: 3 to 6 times body length
HERBIVORE: 10 to more than 12 times body length
OMNIVORE: 4 to 6 times body length
HUMAN: 10 to 11 times body length

CARNIVORE: Simple, short and smooth
HERBIVORE: Long, complex; may be sacculated
OMNIVORE: Simple, short and smooth
HUMAN: Long, sacculated

CARNIVORE: Can detoxify vitamin A
HERBIVORE: Cannot detoxify vitamin A
OMNIVORE: Can detoxify vitamin A
HUMAN: Cannot detoxify vitamin A

CARNIVORE: Extremely concentrated urine
HERBIVORE: Moderately concentrated urine
OMNIVORE: Extremely concentrated urine
HUMAN: Moderately concentrated urine

CARNIVORE: Sharp claws
HERBIVORE: Flattened nails or blunt hooves
OMNIVORE: Sharp claws
HUMAN: Flattened nails

 Make Pie Tote Bag“When we kill animals to eat them, they end up killing us because their flesh, which contains cholesterol and saturated fat, was never intended for human beings, who are natural herbivores.”


“Because humans get atherosclerosis, and atherosclerosis is a disease only of herbivores, humans also must be herbivores.”

William C. Roberts, M.D., editor, American Journal of Cardiology

“Comparative anatomy teaches us that man resembles frugivorous animals in every thing, and carnivorous in nothing; he has neither claws wherewith to seize his prey, nor distinct and pointed teeth to tear the living fibre.”

7 responses to “human anatomy and physiology

  1. nveric says:

    Besides mother’s milk, what food was intended for humans?
    A better question is why are humans able to leave the planet?
    Maybe Gaia designed us this way?

  2. Cheryl Hugle says:

    The answer to the first question is fruits, nuts, seeds, vegetables, leaves, grasses, etc.

    And the answer to the second question is that we are not able to leave the planet. A bounce or two into space does not constitute leaving the planet. Our dependency on mother earth has never been overcome.

    Like all creatures, we seek harmony, comfort, fulfillment. The fact that we are left to do this outside natural feedback and accommodation has resulted in some pretty far fetched ideas of how best to adjust. But, other creatures are no less remarkable in their efforts to find comfort and accomodation in unnatural circumstances:

  3. cj says:

    only humans continal to drink milk as they age. why is that?

  4. jcomeauictx says:

    I don’t follow the argument in the first paragraph. our eating meat has nothing to do with agriculture nor even with animal husbandry, as we had been big game hunters for several tens of thousands of years by then.

    for an opposing view, which is light on diet but heavy on anthropology, see

  5. Cheryl Hugle says:

    Some societies hunted but not all. And hunting was NOT an original human activity (as it was for lions) for providing nutrition. Foraging or fruits, leafy greens and other plant foods was. This is an anthropological fact. Thus, there is no evolutionary argument possible and there is clearly no anatomical adaptation for meat eating. Finally, science is not always science, sometimes it’s just politics (if you know what I mean). No matter the ‘theory’ or ‘evidence’, one still must deal with the fact that humans remain herbivores anatomically and only omnivores culturally. These are the facts that continue to refute confused anthropological theories to the contrary.

  6. This is absolutely fantastic information – thank you for compiling and sharing it.

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