Food Handling

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True   Likely   Speculative
Human Uniqueness Compared to "Great Apes": 
Relative Difference
MOCA Domain: 

Plants make up the bulk of the diet of most primate species. Plants must use morphological, mechanical, or chemical defenses to protect themselves

Chemical defenses include the presence of secondary compounds. Secondary compounds can act as anti-feedants as "digestive inhibitors" or as "toxins". Digestion inhibitors include: tannins, proteinase inhibitors, anti-microbial compounds or lignin. Major classes of toxins include alkaloids, phenolics, tannins, saponins, cyanogenic glycosides, rotenoids and other flavonoids, sesquiterpenes, diterpenes, pyrethrins, and non-protein amino acids and cyanide glycosides (Chapman and Chapman 2002; Rosenthal and Janzen 1979). These secondary compounds can be found in leaves, seeds, pith, husks, flowers, gums, and barks.

Several primate taxa, such as colobine monkeys, have evolved dental and gastrointestinal features that allow them to overcome diets high in secondary compounds (Lambert 1999). Great apes, including humans, do not possess a specialized gut to process foods that are high in secondary compounds and must avoid these compounds in alternative ways.


Humans consume foods with high levels of plant derived secondary compounds that include ascyanide, quinine, morphine, cocaine, caffeine, and nicotine (Glander 1982; Siegler 1977). The plant family Solanaceae contains several foods routinely consumed by a wide variety of human populations that includes foods such as potatoes, tomatoes, eggplant, and pepper (Chaube and Swinyard 1976).

Mechanical processing of secondary plant compounds may include the removal of indigestible or toxic plant parts or cooking, which acts to destroy tannins. For example, among the Hadza hunter-gatherers of Tanzania, several methods of food handling are used. Seed husks of the baobab fruit are winnowed away prior to ingestion and the fibrous quid of certain species of tubers are expelled before consumption.


Chimpanzees have been reported to avoid alkaloid rich fruits (Hladik 1977) and exhibit a preference for ripe fleshy fruits that contain large quantities of tannins when unripe. Chimps process unripe fruit by removing the seeds from the pulp before consumption and discarding any pulp that is tannin rich (Waterman 1984). "Wadging" (Goodall 1986) is an alternative mechanism of seed extraction in which fruit is pressed against the anterior dentition while the fruit juice is sucked out, making a wadge of pulp, skin, fiber, and seeds; the seeds are discarded once the juice has been consumed (Lambert 1999).


Mountain gorillas select leaves that are low in tannins (Watts 1984). They possess an enlarged hindgut relative to chimpanzees and have higher rates of fermentation via cellulose digesting microflora (Bauchop 1978; Chivers and Hladik 1980). Gorillas may also practice geophagia to facilitate consumption of secondary plant compounds (Remis 1997). Gorillas also consume foods that contain spiny plant parts and nettles and employ mechanical removal by folding nettles inside the plant before consumption (Byrne 2001).

The presence of various food handling behaviors among extant great apes suggests that secondary plant compound processing or avoidance behaviors were present in early hominins.




Timing of appearance of the difference in the Hominin Lineage as a defined date or a lineage separation event. The point in time associated with lineage separation events may change in the future as the scientific community agrees upon better time estimates. Lineage separation events are defined in 2017 as:

  • the Last Common Ancestor (LCA) of humans and old world monkeys was 25,000 - 30,000 thousand (25 - 30 million) years ago
  • the Last Common Ancestor (LCA) of humans and chimpanzees was 6,000 - 8,000 thousand (6 - 8 million) years ago
  • the emergence of the genus Homo was 2,000 thousand (2 million) years ago
  • the Last Common Ancestor (LCA) of humans and neanderthals was 500 thousand years ago
  • the common ancestor of modern humans was 100 - 300 thousand years ago

Probable Appearance: 
25,000 thousand years ago
Definite Appearance: 
6,000 thousand years ago


  1. Foraging Challenges of Red Colobus Monkeys: Influence of Nutrients and Secondary Compounds, Chapman, C., and Chapman L. , Comparative Biochemistry and Physiology, Part A, Volume 133, p.861-875, (2002)
  2. Gorillas as seasonal frugivores: Use of resources that vary. , Remis, M. J. , American Journal of Primatology , Volume 43, p.87-109, (1997)
  3. A Preliminary Study of Food Selection by the Orangutan in Relation to Plant Quality, Hamilton, R. A., and Galdikas B. M. , Primates, Volume 35, Issue 3, p.255-263, (1994)
  4. Seed Dispersal by Forest Chimpanzees in Uganda, Wrangham, R. W., Chapman C.A., and Chapman L. J. , Journal of Tropical Ecology, 1994, Volume 10, Issue 3, p.355-368, (1994)
  5. A Case Study of a Plant-Animal Relationship: Cola lizae and Lowland Gorillas in the Lope Reserve, Gabon, Tutin, C. E. G., Williamson E. A., Rogers M. E., and Fernandez M. , 1991, Volume 7, Issue 2, p.181-199, (1991)
  6. Natural and synthetic diets of Malayan gibbons, Chivers, D. J., Raemakers J. J., Else J. G., and Lee P. C. , Primate biology and conservation , Cambridge, UK, p.39-56, (1986)
  7. Seed dispersal by pygmy chimpanzees (Pan paniscus): A preliminary report, Idani, G. , Volume 27, Issue 4, p.441 - 447, (1986)
  8. The Chimpanzees of Gombe, Goodall, J. , Cambridge, MA, (1986)
  9. Food Acquisition and Processing as a Function of Plant Chemistry, Waterman, P. G. , Food Acquisition and Processing in Primates, New York , p.177 - 212, (1984)
  10. Composition of variability in mountain gorilla diets in the ventral Virungas, Watts, D. P. , American Journal of Primatology , Volume 7, p.323-356, (1983)
  11. Orangutans as seed dispensers at Tanjung Puting, Central Kalimantan: Implication for conservation, Galdikas, B. M., and Boer L. E. M. , The Orangutan: Its biology and conservation, The Hague, p.285-298, (1982)
  12. The impact of plant secondary compounds on primate feeding behavior, Glander, K. E. , American Journal of Physical Anthropology, Volume 25, p.1–18, (1982)
  13. Morphology of the gastrointestinal tract in primates: comparisons with other mammals in relation to diet., Chivers, D J., and Hladik C M. , J Morphol, 1980 Dec, Volume 166, Issue 3, p.337-86, (1980)
  14. Herbivores, their interaction with secondary plant metabolites, Rosenthal, G. A., and Janzen D. H. , New York, (1979)
  15. Adaptive Strategies of Primates in Relation to Leaf Eating, Hladik, C. M., and Montgomery G. G. , The Ecology of Arboreal Folivores , Washington, D. C. , p.373-395, (1978)
  16. Biotransformations of xenobiotics by animals, Millburn, P., and Harborne J.B. , Biochemical Aspects of Plant and Animal Coevolution, Volume Proceedings of the Phytochemical Society Symposium, Reading, April, 1977, p.35-73, (1978)
  17. Digestion of leaves in vertebrate arboreal folivores, Bauchop, T., and Montgomery G. G. , The Ecology of Arboreal Folivores, Washington, D. C. , p.193-204, (1978)
  18. Chimpanzees of Gabon and Chimpanzees of Gombe : some comparative data on the diet, Hladik, C.M. , Primate Ecology: Studies of Feeding and Ranging behaviour in Lemurs, Monkeys, and Apes, London, p.481-501, (1977)
  19. The naturally occurring cyanogenic glycosides, Seigler, D. S. , Prog. Phytochem, Volume 4, p.83-120, (1977)
  20. Teratological and toxicological studies of alkaloidal and phenolic compounds from Solanum Tuberosum , Chaube, S., and Swinyard C. A. , 01/1976, Volume 36, Issue 2, p.227 - 237, (1976)
  21. The Mountain Gorilla: Ecology and Behavior, Schaller, G. B. , Chicago, (1963)