|International Vegetarian Union (IVU)|
|The Diet of Early Humans
What did our ancestors eat?
A personal information file by Bronwen Humphries (1994)
Introduction -- Time Scale -- Human Descent -- Ramapithecines -- Australopithecines -- Homo Habilis -- Homo Erectus -- Neanderthal Man -- Homo Sapiens Sapiens -- Early Agriculture -- Middle Ages -- What Were People Programmed to Eat? -- Biological Comparisons with Higher Primates -- Health and Endurance -- Conclusions -- Further Reading
You sometimes hear the argument that humans are "naturally vegetarian" or that they evolved as vegetarians. This is somewhat dangerous to pursue as the scientific evidence all indicates that we are omnivores, i.e., we can survive on a wide variety of plant and animal foods. It also used to be believed that the great apes were all frugivores (fruit-eaters), but recent reseach shows that chimpanzees at least will attack and kill small animals and will eat carrion if they find it. The chimpanzee is thought to be our closest animal relative.
The extreme opposite concept, however, that of Man the Great Hunter, also seems to be untrue. In his book The Rise and Fall of the Third Chimpanzee, Jared Diamond describes how he was invited on a hunt by a tribe in New Guinea who had retained Stone Age technology and habits of thought in the 20th century. The day's total bag was two baby birds, a few frogs, and a lot of mushrooms. Although the men of the tribe frequently boasted of the large animals they had killed, when pressed for details, they admitted that large animals were killed only a few times in a hunter's career. These peoples' stone tools were far more advanced than the stone tools found on prehistoric sites, so Professor Diamond thinks it unlikely that prehistoric hunters could have enjoyed a much higher success rate than present day hunter-gatherer tribes. It seems more likely that early humans ate carrion, small prey like baby birds, and a lot of plant foods. He cites a notable exception to this rule. The first humans to colonise a previously unoccupied island or continent, e.g., Madagascar, New Zealand, and America, found animals so tame that they didn't run away from hunters. In these instances, something like 80 percent of the large birds and mammal species of such an area were exterminated in a relatively short time.
The archeological record does not give a clear, linear story of human development. Also, in the earlier stages of our development, there were obviously several humanoid species existing as co-contemporaries and it is not always clear which one is the direct ancestor of modern Man. You should remember that there is a lot of variation between fossil types classed as the same species, even those from similar periods of time. It seems unlikely that there was a uniformity of characteristics and lifestyle amongst all humans alive at any one time until H sapiens sapiens became the dominant species. Our history is much more of a patchwork of sub-species and differing ways of life. Finally, the experts themselves frequently disagree over what particular fossil finds may mean and how they fit into our "family tree"! However, the the following notes may help.
These bipedal apes appear to be humankind's earliest ancestors, at least amongst the fossil primates that can be identified with any certainty. Unlike modern apes who live in tropical forests, they lived in sub-tropical forests that would not have provided such a constant, year-round food supply, so they seem to have learnt to forage for food on the ground. Ramapithecines disappear from the fossil record about 8 million years ago.
[later note from a visitor to this site: It now seems that Ramapithecus is no longer considered a human ancester. According to the Columbia Encyclopedia, 2001, "Fossils of Ramapithecus were discovered in N. India and in E. Africa, beginning in 1932. Although it was generally an apelike creature, Ramapithecus was considered a possible human ancestor on the basis of the reconstructed jaw and dental characteristics of fragmentary fossils. A complete jaw discovered in 1976 was clearly nonhominid, however, and Ramapithecus is now regarded by many as a member of Sivapithecus, a genus considered to be an ancestor of the orangutan.]
Primates with definite humanlike features had developed by about 5 million years ago. Among them were a group known as Australopithecines or Southern Apes. They were widespread in Africa and inhabited parts of Asia as well. A robustus was a vegetarian but does not appear to be a direct ancestor of Homo sapiens. A africanus was smaller and seems to have already developed the hunter-gatherer way of life that has been characteristic of human beings for most of our existence. It walked on two legs and used tools but the skull was still apelike. It appears to have evolved from an earlier type called A afarensis. What is not clear is whether A africanus simply kept on evolving until it became Homo erectus, or whether it was simply a contemporary of the true human ancestor, presumably in a form that we haven't yet discovered in the fossil remains.
A recent article in New Scientist (14.5.94), suggests that A afarensis developed bipedalism in order to reach fruits growing on small trees. The pelvis of the fossilised remains (including the famous "Lucy") is very wide, which would have provided good support when standing upright to feed, but would not have been very efficient for walking any distance.
In September 1994, there were reports of a fossil find that is probably an even earlier ancestor, now called Australopithecus ramidus, which is dated to about 4.4 million years ago (reported in New Scientist 1.10.94). A ramidus remains were found in association with bones from colobus monkeys, kudus and other tree-loving animals which suggests it lived in woods and forests. Insufficient remains were found to decide if A ramidus walked upright or had human-like features but the teeth were covered in thin enamel, suggesting it ate mainly vegetation. Although the press called it "the missing link" this isn't really true as it lies well down the "fork" leading to Homo sapiens on the primate family tree. Human and apes diverged between 8 and 6 million years ago but so far, no fossils of creatures resembling apes or humans have been found of that date in Africa.
[later note from a visitor to this site: The article mentions Australopithecus ramidus discovered in 1994, as a possible hominid earlier than A afarensis. This has since been argued for a new genus as Ardipithecus ramidus. Although contested, the evolution diagrams now mostly use Ardipihtecus ramidus.]
Alan Walker of Johns Hopkins University reported in the American magazine Vegetarian Times (June 1991) claims that there is evidence that Homo habilis scavenged dead animals that had been killed and partially eaten by other creatures.
Homo Habilis gradually evolved into Homo erectus.
H erectus fossils date back to about one and half million years ago. They were tool users and fully adapted to walking upright on two legs, with a brain case only slightly smaller than modern humans, but still had some ape-like features such as a low forehead, heavy jaw and large teeth. It was H erectus that expanded northwards into the cooler areas of the world. Fire was in use and H erectus hunted and ate cooked meat. Alan Walker (see reference above) says the wear on the teeth of Homo erectus indicates a varied diet including meat. A female skeleton from 1.6 million years ago has symptoms of hypervitaminosis, ie excess of vitamin A which is most likely caused by eating carnivore livers. They possibly started off as scavengers and developed into hunters.
According to an article in New Scientist (Human Origins: The Challenge of the Java Skulls, 7.5.94), H Erectus is "clearly a different kind of animal from earlier hominid species", being "much more human in stature and build ...and, judging from the structure of its teeth and the content of associated archaeology sites, it apparently included significant amounts of meat in it's diet."
The Neanderthals were the dominant human species in Europe between 130,000 and 40,000 years ago. There's no doubt that they were hunters. Recent research conducted at the Pierre and Marie Curie University, Paris (reported in The Times, 5.9.91) suggests they had little interest in vegetable foods at all. Homo sapiens Neanderthalis was closely related to modern humans, but are not our direct ancestors.
Homo sapiens sapiens, or modern man, first appeared in the fossil record about 40,000 years ago. There have been no significant genetic changes during that period. Agriculture is a comparatively recent trend, developing about 10,000 years ago and apart from the retention of intestinal lactase into adulthood, does not seem to have had any major effect on our evolution. Modern agricultural methods and food processing are too recent to have made any genetic impact at all. Therefore, the range of diets available to pre-agricultural men and women are still the range of diets we are programmed to eat. Modern hunter-gatherer tribes have eating patterns that are most likely to resemble those of pre-agricultural human beings.
Archaeological evidence suggests that during the transitional period between hunter-gatherer and farmer, people were under substantial nutritional stress. A comparison of skeletons from these times shows they were averaging 10cms shorter, about 7 kilos lighter and showing more symptoms of skeletal disease linked to nutritional stress (e.g., osteoporosis) than skeletons from a few thousand years earlier. The hunter-gatherer diet is nutritious and well-balanced so it is postulated that humans were forced to switch to agriculture by rising population levels. We were just too successful at the hunting-gathering lifestyle! (ref: Foraging for Nature's balanced Diet:Robin Dunbar/New Scientist 31.8.91)
During the middle ages, at least in Britain, vegetables were seen largely as pauper's food and the rich consumed vast quantities of meat. A record of a three-course dinner served in the reign of Richard II included: larded boar's head, pottage of liver and kidneys, beef, mutton, pork, roasted rabbit, duck, pheasant, chicken, one pottage of almonds, minced onions and small birds like linnets and sparrows, more rabbits, hares, teals, woodcock, and snipe. This was considered a relatively modest dinner and as you can see vegetables appear only as a garnish or flavouring (described in The English Medieaval Feast by W.Mead).
The following is a summary of a talk given by Dr David Ryde to a Symposium organised by The Vegetarian Society, 19.4.86.
Dr Ryde began by describing how, during periods of abundance, most creatures eat only a narrow range of foods. For example lions flourish on zebra and wildebeest meat, songbirds on worms and grubs, berries etc, cattle, sheep and horses on different kinds of grasses and apes live largely on fruits and vegetables. These niches tend to be transgressed only in times of shortage. What foods then has Nature programmed Man to eat in order to maintain health growth. activity and reproduction? Boyd and Konner (1985) state that "From about 24 to 5 million years ago fruits appear to have been the main dietary constituent for hominids...since 4.5 million years ago our ancestral feeding pattern included increasing amounts of meat.
Compared to other primates, modern man eats a great range of foods and this probably relates more to his use of cutting and crushing implements and to the later control of fire. The fact that raw meat is almost universally cooked to make it palatable and digestible suggests that prepromethean man did not eat it in large amounts. Cooking denatures protein, melts out fat and breaks down the fibrous tissue. Carnivores gulp down lumps of meat, their sharpened molars tearing it like scissors for digestion to begin in the stomach. Herbivores with flatter molar teeth crush the cellulose-walled plant cells and begin carbohydrate digestion in the mouth with the enzyme ptyalin (amylase). This enzyme occurs in cows, pigs, rabbits and humans but it doesn't occur in carnivores.
Human teeth are omnivorous in design, yet more closely resemble primate teeth whose possessors live largely on fruit and plants. Carnivorous jaws swing vertically while herbivorous and human jaws swing vertically to tear and laterally to crush, suggesting we are more akin to herbivores.
Carnivores have a bowel length about 3 times the trunk length, in herbivores it is about 15 times longer and in humans 10 times longer, again suggesting we are closer to herbivores.
The DNA difference between gorillas, chimpanzees and humans are reported as being under one percent, less than between different species of horse. The digestive tracts are almost identical. Dr Ryde told an amusing anecdote of an occasion when he showed a surgeon specialising in alimentary surgery an illustration of a gorilla's digestive tract and asked if it belonged to a man or woman. The surgeon replied "It's difficult to tell!" and was very surprised to hear the answer was neither. These high primates, gorilla and chimpanzee, are described as herbivores and opportunist carnivores, i.e., they eat mainly fruits and vegetables but will take eggs, insects, lizards and other small creatures if easily available or when very hungry.
Hamilton and Busse in 1978 showed that among 21 primates animal food consumption is inversely related to body weight, i.e., the smaller the primate, the more meat eaten. The smallest weighed 65g and ate 70% dietary animal matter, the largest, the gorilla weighed 126kg and ate 1 or 2% animal matter, as does the orangutan at 58kg. Humans on this scale stand between gorillas and orangutans, likewise indicating a diet with only 1 or 2% animal matter.
Walker, as reported by Briben and Cherfas in 1982, has been studying minute abrasions on the teeth of fossils and living species with an electron microscope. He has shown that the marks on the teeth of Australopithecus robustus (ancestral man of 4 million years ago) indicate he was a fruit eater.
It seems reasonable to speculate that one higher primate was able, several million years ago when the climatic chips were down and the forests receding, to increase its food repertoire by applying its knowledge and skills to hunting away from tree cover. He speculates that Homo sapiens is a more efficient herbivore than carnivore, but crushing and cooking makes meat more digestible and also makes it easy to consume amounts in excess of needs. Pliocene climatic changes of ice age and drought rendered food less plentiful and to survive, early man began to adapt towards a gatherer-hunter existence about 3.5 million years ago. Probably humans slowly migrated from Africa and adapted to temperate regions by consuming more high fat foods. The discovery of how to harness fire about half a million years ago further increased alimentary options and proved to be a great social and nutritional revolution, as was agriculture, established only about 10,000 years ago.
In his own practice, he found obese people who had not been helped by traditional advice on dieting, achieved good results by changing to a vegetarian diet and a patient with a 15 year history of angina was put on vegan diet and after a month felt "marvellous". His angina disappeared, he lost 20lbs in weight, his blood pressure dropped 55 points and he was able to walk 4 miles without trouble.
One argument against a vegan diet is the reported deficiencies of vitamins B12 and D and the minerals calcium and iron. Gorillas are coprophageous (eat their own stools) and this may allow B12 synthesised in the hind gut, where it cannot be absorbed, to be passed to the foregut, where it can be assimilated.
Vitamin D deficiency would not be a problem if we didn't wear clothes. Supplements are a socially acceptable alternative to coprophagy and nudity.
Pritikin (1985) writes that "The high protein intake which is common in the developed nations causes a negative mineral balance, drawing calcium from bone to neutralise the acid products of protein metabolism." It is those who eat meat who need extra calcium.
Menstruation in gorillas recurs about 2 years after parturition but may be delayed a further two years by continued breast-feeding (Fossey 1985). In the Kung people, one of the few remaining gatherer-hunter societies, childbirth also occurs about once every four years and breast-feeding continues two and a half years at least. Since menstruation whilst breast-feeding is rare, a major cause of iron deficiency is removed. Gorillas also eat the placenta to recover minerals.
Modern carnivorous society then imposes abnormal conditions on vegetarians and vegans and it is realistic for them to compensate with supplements.
Dr Ryde concluded by stating his hypothesis that Pliocene man was a herbivore food gatherer, an opportunist carnivore and perhaps a coprophagist. Adverse climatic changes and control of fire led to an exploitation of carnivorous options. Currently we are still adapting, for better or worse, to the nutritional changes deriving from the creation of agriculture, animal husbandry and a food industry. Modern man's destructive and addictive habits and minimal physical activity are unphysiological, productive of excess weight and disease and lead to early degenerative changes. The civilised human lifestyle bears comparison to that of the domesticated animal. If people reduced their animal protein, salt, sugar and fat consumption and compensated with appropriate fresh plant produce, they would be closely following the NACNE recommendations. "yesterday's food will become tomorrow's food".
The Rise and Fall of the Third Chimpanzee, by Jared Diamond, Vintage. The early chapters of this book give a very readable summary of the evolution of humans and show how closely we are related to the living species of apes. There is also a chapter that describes the effects of agriculture on the health and diet of early humans.
Getting Here: The Story of Human Evolution, by William Howells, Compass. Although it doesn't go into details of diet, this book does provide a very readable, fairly comprehensive account of human evolution, and an understanding of how we fit into the primate family tree.
Compiled by Bronwen Humphrey, updated: 30.09.94.