12.6.11

Anatomy - Human versus Animal Eating Mechanisms

From: The Comparative Anatomy of Eating - Vegsource.com
"Humans are most often described as "omnivores." This classification is based on the "observation" that humans generally eat a wide variety of plant and animal foods. However, culture, custom and training are confounding variables when looking at human dietary practices. Thus, "observation" is not the best technique to use when trying to identify the most "natural" diet for humans. While most humans are clearly "behavioral" omnivores, the question still remains as to whether humans are anatomically suited for a diet that includes animal as well as plant foods.

A better and more objective technique is to look at human anatomy and physiology."

Extract:
In conclusion, we see that human beings have the gastrointestinal tract structure of a "committed" herbivore. Humankind does not show the mixed structural features one expects and finds in anatomical omnivores such as bears and raccoons. Thus, from comparing the gastrointestinal tract of humans to that of carnivores, herbivores and omnivores we must conclude that humankind's GI tract is designed for a purely plant-food diet.
SUMMARY
Facial Muscles
Carnivore Reduced to allow wide mouth gape
Herbivore Well-developed
Omnivore Reduced
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
Carnivore Large
Herbivore Small
Omnivore Large
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
Chewing
Carnivore None; swallows food whole
Herbivore Extensive chewing necessary
Omnivore Swallows food whole and/or simple crushing
Human Extensive chewing necessary
Saliva
Carnivore No digestive enzymes
Herbivore Carbohydrate digesting enzymes
Omnivore No digestive enzymes
Human Carbohydrate digesting enzymes
Stomach Type
Carnivore Simple
Herbivore Simple or multiple chambers
Omnivore Simple
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
Colon
Carnivore Simple, short and smooth
Herbivore Long, complex; may be sacculated
Omnivore Simple, short and smooth
Human Long, sacculated
Liver
Carnivore Can detoxify vitamin A
Herbivore Cannot detoxify vitamin A
Omnivore Can detoxify vitamin A
Human Cannot detoxify vitamin A
Kidney
Carnivore Extremely concentrated urine
Herbivore Moderately concentrated urine
Omnivore Extremely concentrated urine
Human Moderately concentrated urine
Nails
Carnivore Sharp claws
Herbivore Flattened nails or blunt hooves
Omnivore Sharp claws
Human Flattened nails

Read more: The Comparative Anatomy of Eating - Vegsource.com