is a line-by-line critique of the article: Milton, K. 1999. A hypothesis
to explain the role of meat-eating in human evolution. Evolutionary
KM: Primates, particularly humans, are
noted for their relatively large brains and considerable behavioral plasticity.
In contrast to behavior, morphological structures tend to alter
only slowly over time, generally in response to particular selective pressures.
KM: Here I will argue that the pattern
of gut anatomy and digestive kinetics characteristic of ancestral Hominoidea
imposed certain constraints on their descendents in terms of diet. Meat-eating
in the human lineage (Homo spp.) appears to be one way of circumventing
KM: SUMMARY OF THE ARGUMENT Extant apes
and humans are descended from a common plant-eating ancestor.
KM: Great apes and humans also show similarities
in many features of gut anatomy and a similar pattern of digestive kinetics,
passing ingesta at a relatively slow rate. This kinetic pattern appears
to be a conservative feature of the lineage.
KM: In mammalian herbivores, an increase
in body size is generally associated with a decrease in dietary quality.
Thus, any hominoid increasing in body size and continuing to focus largely
on plant foods is likely to show lowered dietary quality and decreased
energetic input per unit of food consumed.
KM: Extant apes and humans show various
dietary strategies for dealing with the limitations set by their common
pattern of gut anatomy and digestive kinetics.
KM: Over their evolutionary history, orangutans
and gorillas appear to have followed a dietary strategy associated with
increased body size and lowered dietary quality. Because of their large
size, both species can and often do subsist on fairly low quality foods
such as mature foliage, bark, and unripe fruits. But they have paid for
this compromise in dietary quality. For example, relative to many other
anthropoids, orangutans, mountain gorillas, and most lowland gorillas
are rather passive primates that lack notable sociality, probably because
they lack the energy required for a more active life.
KM: Chimpanzees, on the other hand, have
followed a different dietary strategy. Though they have fairly large bodies,
chimpanzees, like many cercopithecine monkeys, eat a high-energy diet
consisting in large part of ripe fruits. In this manner, though often
only with considerable effort, including extensive travel and the occupation
of large home ranges, chimpanzees generally are able to secure sufficient
high-quality food to maintain their active and highly social lives.
KM: Humans, who are believed to have evolved
in a more arid and seasonal environment than did extant apes, illustrate
a third dietary strategy in the hominoid line. By routinely including
animal protein in their diet, they were able to reap some nutritional
advantages enjoyed by carnivores, even though they have features of gut
anatomy and digestive kinetics of herbivores.
KM: Using meat to supply essential amino
acids and many required micronutrients frees space in the gut for plant
KM: In addition, because these essential
dietary requirements are now being met by other means, evolving humans
would have been able select plant foods primarily for energy rather than
relying on them for most or all nutritional requirements.
KM: This dietary strategy is compatible
with hominoid gut anatomy and digestive kinetics...
KM: ... and would have permitted ancestral
humans to increase their body size without losing mobility, agility, or
sociality. This dietary strategy could also have provided the energy
required for cerebral expansion.
KM: All extant apes eat strongly plant-based
diets composed of the fruits, leaves, flowers, and bark of tropical forest
trees and vines. Most apes also consume some invertebrates and, less commonly,
KM: In general, however, the gut anatomy
of all extant apes is quite similar. Human gut anatomy is quite similar
to that of other extant hominoids. Mitchell remarked that primitive humans
were probably omnivorous with a [cultural-ljf]
tendency toward carnivory, but pointed out that "the result
has not yet been any marked adaptive change in the character of the gut
as compared with that of the Anthropoid Apes, although in the latter the
diet is omnivorous with the strongest leaning toward the vegetable side."
KM: In 1904, based on study of the comparative
anatomy of the hominoid gut, Elliott and Barclay-Smith suggested that
the structure of the human gut actually appeared to be closer to that
of a herbivore than an omnivore.
KM: The marked sacculations characteristic
of the human and ape colon also support the view that the ancestral line
giving rise to all extant hominoids was strongly herbivorous. Further
evidence of a plant-based diet for ancestral hominoids comes from the
study of dentition, which suggests that many fossil hominoids were largely
KM: Thus, using data from various lines
of evidence, there seems to be general consensus that humans come from
an ancestral lineage that was strongly dependent on plant foods, and that
human gut anatomy is very similar to that of other extant hominoids. Despite
this basic similarity, there is one striking difference between the gut
anatomy of humans and apes. This difference is in the size relationship
of different sections of the gut. In all apes, the greatest gut volume
is in the colon (>45% of total), with only about 14 to 29% of the total
gut volume in the small intestine. For humans, the greatest gut volume
is in the small intestine (>56%); only about 17 to 23% of the total
gut volume is in the colon.
KM: Compared to apes, modern humans also
have a relatively small total gut for their body size. These size relationships
make it clear that among extant Hominoidea, humans are the outlier taxon.
This suggests that humans rather than apes have deviated most markedly
from the ancestral condition in terms of gut proportions and diet.
KM: However, in comparing gut proportions of
apes and humans, ... my concern is with the inherited pattern of gut proportions
characteristic of all extant apes on the one hand and all modern humans
on the other - a proportional relationship that I hypothesize is found
in all apes regardless of their environmental circumstances or genetic
background and one characteristic of all humans regardless of their environmental
circumstances or genetic background. The dominance of the small intestine
in humans suggests adaptation to a high-quality diet composed of foods
that are nutritionally dense, volumetrically concentrated, and amenable
to digestion in the small intestine.
KM: In contrast, dominance of the colon
in extant apes suggests adaptation to a diet with considerable refractory
plant material that cannot be digested in the small intestine and that
passes into the voluminous hindgut, where it is retained while certain
essential functions such as fermentation of refractory materials are carried
KM: Gut proportions are one factor that
can influence digestive parameters and food choices in the natural environment,
but another important factor that needs consideration is gut kinetics.
Gut kinetics refers to the pattern of movement of ingesta, both
particulate and liquid, through the digestive tract.
KM: Milton and Demment examined the pattern
of digestive kinetics of common chimpanzees (Pan troglodytes) fed diets
of two fiber levels. One diet contained 14% neutral detergent fiber; the
other contained 34% neutral detergent fiber. Ingesta passed more rapidly
on the high fiber diet (mean transit time = 38 hours on the high-fiber
diet and 48 hours on the low-fiber diet. Mean transit time is an estimate
of the average time ''particles'' of marker take to pass through a system
of unknown or undefinable compartments). Because ingesta passed more rapidly
when dietary quality was low (high-fiber diet), the chimp gastrointestinal
tract had less time to process ingesta flowing through it.
KM: However, because this lower-quality
food passed more rapidly, chimpanzees could eat more food per unit of
time. With only moderate alterations in dietary quality in the natural
environment, the end result of both passage rates in chimpanzees would
probably be about the same; that is, chimpanzees would be able to meet
their daily requirements for energy and nutrients on both diets.
KM: Extensive work has been carried out
on the passage kinetics of humans. For example, a detailed study
of human passage kinetics at Cornell University showed a mean transit
time of 62.4 hours for subjects on a 0% fiber diet and 40.9 hours for
human subjects on a 17.3% fiber diet.
KM: However, an extensive body of data
supports the view that in humans higher-quality diets tend to pass more
slowly than do fibrous, lower-quality diets.
KM: Relative to wild apes, most human
populations eat foods that are amazingly refined, digestible, and calorie-rich,
as well as low in plant fiber. In humans, much food preparation (nonsomatic
digestion) occurs before a food item is ever brought into contact with
the mouth and gastrointestinal tract, a behavior that could ultimately
have affected human gut proportions.
KM: However turnover of this high-quality
ingesta in humans typically is quite slow.
HOMINOID EVOLUTION Like the Carnivora, extant Hominoidea seem ''stuck''
with their ancestral pattern of digestive kinetics and basic features
of gut anatomy.
KM: The fossil record shows that during
the early to middle Miocene, hominoids reached their greatest level of
diversity. In general, Miocene apes were characterized by a frugivorous
pattern of molar morphology, though some evidence suggests that larger
middle-Miocene apes may have had omnivorous tendencies.
KM: I will compare the dietary niches
of extant pongids to illustrate how meat-eating may have permitted human
ancestors to overcome the energetic constraints imposed by increasing
body size in the hominoid lineage.
KM: Not surprisingly, in view of their
size and strongly plant-based diet, gorillas (particularly mountain gorillas)
and orangutans are often forced to turn to lower quality plant foods --
mature leaves, bark, pith, and unripe fruits --when sufficient ripe fruits
and high-quality young leaves are not available.
KM: But many such features appear to be
resistant to changes that, at least theoretically, might seem useful.
KM: As discussed, there seems general consensus
that extant hominoids come from a strongly herbivorous ancestral lineage.
KM: Although some western lowland gorilla
groups at times eat a considerable amount of fruit and may range as far
as 2.3km/day, it seems to be generally accepted that lowland gorillas
eat more vegetative plant parts than do chimpanzees and fall in an intermediate
ecological position between chimpanzees and bonobos on the one hand and
mountain gorillas on the other.
KM: In short, even lowland gorillas do
not appear to be as active, agile, and socially complex as are members
of the genus Pan. I hypothesize that, due to features of their almost
exclusively plant-based diet, in combination with features of their common
hominoid digestive tracts, energy input in these great apes may often
be sufficiently limited such that nonessential behaviors are not favored.
KM: In other words, I do not believe that
orangutans and gorillas have sufficient ''extra'' energy to be more active
KM: Members of the genus Pan [chimp]
eat a specialized diet composed, in large part, of succulent ripe
fruits. They supplement this basic fruit diet with select protein-rich
young leaves, buds, and flowers, as well as animal matter (particularly
invertebrates but also some vertebrates).
KM: WHERE DO WILD CHIMPANZEES GET PROTEIN?
The fact that the chimpanzee diet is heavily dominated by fruits raises
the question of how these apes obtain the protein they require each day.
KM: Although wild fruits as a class are
low in protein, fruits average 6.5 +/- 2.6% protein dry weight (range,
3.2% to 12.6%).
KM: Common chimpanzees, particularly females,
also often '' fish'' for termites and ants, sometimes devoting hours per
day to this activity. This suggests that although termites and ants are
small, the nutritive benefits they provide are worth this considerable
investment of time.
KM: Gastric (stomach) emptying time in
human subjects fed bread diets is 4 to 5 hours.
KM: If a similar gastric emptying rate
prevails in wild chimpanzees, they should be able to fill the stomach
several times each day, retaining refractory materials (seeds, seed coats,
pectic substances, cellulose, hemicelluloses) in the cecum and proximal
colon for fermentation activities.
KM: WHY NOT EAT MEAT?
KM: Options for any mammal's diet are limited.
Food has to be either plants or animals or a mix of both, and has to supply
all nutrients or their precursors that are essential for that particular
animal. What spells the difference between species in terms of diet are
the types and proportions of foods from each of these two basic dietary
categories that can be efficiently exploited. In terms of gut anatomy
and digestive kinetics, meat, at least up to some maximum percentage of
diet, should pose no problem for a hominoid.
KM: In captivity, for example, boned meat
(raw beef and cooked chicken) was so well digested by common chimpanzees
that it typically produced no visible residues in feces.
KM: However, hominoids are not carnivores
and have neither the gut anatomy nor digestive physiology of Carnivora.
As Speth and Speilman discussed, healthy humans are not known to derive
any particular benefit from eating excessive amounts of protein; indeed,
some evidence suggests that excessive protein consumption is unhealthy
KM: Excessive protein consumption '' idles''
the body engine faster while producing no demonstrably favorable metabolic
effects. In addition to these concerns, catabolizing protein for energy
is not practical for mammals such as hominoids if other energy substrates
are available, the reason being that the metabolic costs of protein conversion
greatly exceed those of converting carbohydrates and fat. Perhaps most
important, adult humans apparently cannot catabolize sufficient protein
to meet more than 50% of their daily energetic requirements.
KM: Though animal matter presumably did
not serve as a primary source of calories for evolving humans, there is
no reason why moderate amounts of animal matter could not have been used
as an important dietary component if it could be secured.
KM: I depart from those who suggest that
meat may have been only a marginal food for early humans. I have come
to believe that the incorporation of animal matter into the diet played
an absolutely essential role in human evolution, though I leave it to
others to determine prey types and sizes, means of procurement, and the
KM: Human ancestors appear to have evolved
in a somewhat arid, seasonal, and fairly open environment where ripe fruits
and young leaves probably were not available throughout the year. Animal
protein not only provides all of the amino acids humans require in the
proper complements and proportions for human protein synthesis, but also
is more efficiently digested than plant protein.
KM: A hominoid would thus need to eat
fewer grams of meat to satisfy all protein requirements than it would
if protein requirements were being met from plant parts even of very high
KM: Perhaps equally important, animal tissues
also supply many essential minerals and vitamins that humans require.
following color scheme is used: red for 2-5 times the nutritional content
in beef, orange for
5-10 times, yellow for 10-100 times, and green for greater than 100 times the amount in beef.
|energy, Kcal||322||607||573||541||276||271||276||306||360||323||656||884||870||290||316||296||32||energy, Kcal|
|pro, %||25.6||24.4||17.7||24.5||9.1||31.3||9.1||6.2||23.2||6||14.3||22.8||57.5||13.4||9.6||0.4||pro, %|
|fat, %||23.5||56.6||49.7||45.8||7.4||5.2||7.3||0.3||9.7||20.1||66.2||100||49.6||7.7||20.9||1||0.3||fat, %|
|Ca, mg||9||58||975||43||1890||176||1890||625||39||646||176||116||120||57||11||12||Ca, mg|
|P, mg||198||464||629||1174||201||548||201||52||842||105||600||705||118||1677||294||11||P, mg|
|Fe, mg||2.2||3.1||14.6||15||124||53.9||123.6||21.4||6.3||8.7||3.4||6.8||28.5||18.5||1.7||0.2||Fe, mg|
|Na, mg||62||1||11||18||55||391||55||102||12||243||2||3||1048||5||13||7||Na, mg|
|K, mg||347||524||468||807||814||6300||814||1125||892||264||600||689||1363||1485||1534||146||K, mg|
|Mg, mg||24||202||351||535||220||372||220||770||239||1.1||225||354||195||781||132||18||Mg, mg|
|Zn, mg||5.4||3.4||7.8||7.5||6.2||6.1||6.2||5.8||12.3||1.1||4.6||5.1||2||6||7.7||0.1||Zn, mg|
|Cu, mg||0.1||1.0||4.1||1.4||0.9||0.5||0.9||0.6||0.8||0.3||1.8||1.8||6.1||0.7||5.2||0.1||Cu, mg|
|Mn, mg||0||4.3||2.5||3.0||220||1.3||7.9||4.3||13.3||30||0.8||2||1.9||14.2||1.2||Mn, mg|
|Se, mcg||24.1||17||5.7||5.6||4.6||32.3||4.6||7.4||79.2||5.9||2960||59.5||7.2||15.6||136||0.6||Se, mcg|
|Vit A, IU||296||9||380||3800||63,240||3800||530||50||570||767||Vit A, IU|
|Vit E||0.2||2.6||2.3||1.0||1.7||1.7||5||1.7||7.6||192.4||50.3||5||6||0.1||0.1||Vit E|
|Thiamin, mg||0.1||0.2||0.8||0.2||0.5||1||0.5||1.9||0.1||1||2.3||2.4||2.8||0.3||Thiamin, mg|
|Niacin, mg||4.3||0.7||4.5||1.7||4.9||10.4||4.9||0.2||6.8||1.6||1.6||4.5||12.9||34||14.1||0.4||Niacin, mg|
|B-6, mg||0.4||0.6||0.9||0.2||1.2||1.4||1.2||0.3||1.3||1.3||0.3||0.8||0.4||4.1||1||B-6, mg|
|Folate, mcg||8.0||66||97||58||274||1535||274||580||281||93||4||227||94||63||163||14||Folate, mcg|
|B-12, mcg||2.4||B-12, mcg|
|Vit C, mg||0||3.2||1.9||50||149||50||80.8||0.7||1.4||10.1||3.5||1678||Vit C, mg|
|Cholesterol, mg||83||Cholesterol, mg|
So, the facts indicate that KM's unsupported claims about the nutritional superiority of "animal tissues" are simply wrong. She could have checked the data, but chose not to in service of the meatarian propaganda campaign.
KM: We need to bear in mind that carnivores
and omnivores do not eat only muscle tissue or only muscle and fat but
instead eat brains, viscera, bone marrow, the liver, and other organs.
These different animal tissues provide different types and proportions
of particular essential nutrients. In this sense, the eating of different
body parts by a carnivore resembles the feeding behavior of a herbivore,
which consumes plant foods of different types to obtain a better dietary
mix and thereby improve overall dietary quality.
KM: Humans able to satisfy their total
protein and much of their essential mineral and vitamin requirements with
animal matter rather than plants would free space in their gut for energy-rich
plant foods such as fruits, nuts, starchy roots, other plant parts, or
KM: Jones has pointed out that a disproportionately
large number of the major food plants domesticated by humans are cyanogenic.
If this is an ancient trend in human food habits, the incorporation of
animal protein, with its high methionine content, in the diet of early
humans could have had considerably utility. An adequate supply of sulfur-containing
amino acids is essential in the detoxification of cyanogenic plant foods.
Animal protein may therefore have permitted early humans to use, or to
use more heavily, such cyanogenic but energy-rich foods.
KM: Using animal matter primarily to satisfy
requirements for essential nutrients and plant foods primarily for energy
is a dietary strategy that is compatible with hominoid gut anatomy and
digestive kinetics as well as evidence from the human fossil and archeological
KM: Such a diet, because of its high quality,
would have permitted evolving humans to avoid the constraints gorillas
and orangutans suffered as a result of body size increases (lowered dietary
quality along with lowered mobility and sociality).
KM: This dietary breakthrough in the human
lineage presumably was achieved through both technological and social
innovations that permitted early humans to greatly improve their net returns
from foraging by simultaneously exploiting foods from two trophic levels
while, at the same time, lowering dietary bulk.
KM: One critical aspect of this dietary
trajectory is that once animal matter entered the human diet as a dependable
staple, the overall nutrient content of plant foods could drop drastically,
if need be, so long as the digestible calories were present.
KM: Many underground storage
organs, for example, are a rich source of calories but are almost devoid
of nutrients; some contain cyanogenic glycosides.
|energy, Kcal||322||25||43||118||105||149||109||74||69||72||65||160||21||36||43||energy, Kcal|
|pro, %||25.6||2.2||1||1.5||1.6||6.4||4.8||2.6||1.7||1.5||4.2||1.4||2.5||1.2||1.6||pro, %|
|fat, %||23.5||0.2||0.2||0.3||0.5||0.6||0.1||0.7||0.2||0.2||0.3||0.2||0.2||0.2||fat, %|
|Ca, mg||9||16||27||17||22||181||128||45||18||41||6||16||114||47||16||Ca, mg|
|P, mg||198||58||44||55||28||153||80||100||27||51||98||27||24||58||40||P, mg|
|Fe, mg||2.2||1.2||0.5||0.5||0.6||1.7||1||1.2||0.5||0.8||2.2||0.3||1.6||0.5||0.8||Fe, mg|
|Na, mg||62||7||35||9||13||17||17||40||13||5||26||14||18||20||78||Na, mg|
|K, mg||347||450||323||816||204||401||568||556||415||308||454||271||82||337||325||K, mg|
|Mg, mg||24||24||15||21||0.4||25||69||23||43||38||25||21||18||23||23||Mg, mg|
|Zn, mg||5.4||0.3||0.2||0.2||0.3||1.2||1.6||0.4||0.3||0.3||0.6||0.3||0.2||0.3||0.4||Zn, mg|
|Cu, mg||0.1||0.1||0.2||0.2||0.3||0.2||0.3||0.2||0.1||0.1||0.1||0.1||0.1||Cu, mg|
|Mn, mg||0||0.2||0.1||0.4||0.4||1.7||0.4||23||0.2||0.2||0.2||0.4||0.2||0.2||0.3||Mn, mg|
|Se, mcg||24.1||0.4||1.1||0.7||0.6||14.2||0.7||0.7||0.7||0.7||0.7||0.7||0.9||0.7||0.7||Se, mcg|
|Vit A, IU||28129||20063||46||19||25||6108||580||38||Vit A, IU|
|Vit E||0.2||0.5||0.2||0.3||0.3||0.4||0.2||0.3||0.3||Vit E|
|Thiamin, mg||0.1||0.1||0.1||0.1||0.1||0.2||0.1||0.2||0.1||0.1||0.1||Thiamin, mg|
|Niacin, mg||4.3||1.4||0.9||0.6||0.7||0.7||0.7||0.4||0.7||0.3||1.7||0.9||0.4||0.7||0.3||Niacin, mg|
|B-6, mg||0.4||0.2||0.1||0.3||0.3||1.2||0.3||0.3||0.2||0.2||0.3||0.1||0.1||0.1||0.1||B-6, mg|
|Folate, mcg||8.0||31||14||23||14||3.0||18||13||11||23||338||27||41||21||109||Folate, mcg|
|B-12, mcg||2.4||B-12, mcg|
|Vit C, mg||0||16.9||9.3||17.1||22.7||31.2||41.9||44||5||3||1.9||20.6||25.8||25||4.9||Vit C, mg|
|Cholesterol, mg||83||Cholesterol, mg|
Thus, we see
that plant roots are generally significantly richer than beef in carbohydrates,
fiber, calcium, potassium, magnesium, Vit A, Vit E, thiamin, pantothenic
acid, folate, and Vit C. Clearly, they are most certainly not "almost
devoid of nutrients" as KM claims, without support!
KM: Grains, too, are a rich source of calories
but most species lack some essential nutrients humans require and many
contain cyanogenic glycosides.
KM: But with animal matter in the diet
to supply many essential nutrients, including sulfur-containing amino
acids, the low nutritional value of some plant foods should not pose a
barrier to human feeders as long as the digestible energy is there and
any harmful secondary compounds can be detoxified.
KM: Another important aspect of meat-eating
concerns the increasing importance, as evolution progressed, of higher-quality,
volumetrically concentrated foods for infants and children.
KM: As the World Health Organization states:
''A newborn infant needs dietary protein that contains 37% of its weight
in the form of essential amino acids, whereas for adults the figure is
less than half - about 15%. This has led many to suspect that protein
quality is of limited relevance to adults.... Protein quality is of great
importance in rapidly growing young animals which are actively depositing
new body protein.''
KM: I depart from those who suggest that
meat may have been only a marginal food for early humans. I have come
to believe that the incorporation of animal matter into the diet played
an absolutely essential role in human evolution.
KM: Current evidence offers strong support
for the critical role of micronutrients in the proper development and
growth of human infants. The high nutritional value of animal matter,
not only as a source of essential amino acids, but also as a concentrated
supply of micronutrients, seems particularly critical.
KM: Because of the increase in the ratio
of metabolic requirements to gut capacity in homeotherms, [warm-blooded
animals] eating a diet high in bulky plant material could pose
virtually insurmountable problems for small children, with their high
energetic and nutrient demands, as well as large brain relative to body
KM: Raw meat, organs, brains, viscera,
and bones are concentrated sources of iron, calcium, iodine, sodium, and
zinc, vitamin A, many B vitamins, vitamin C and other essential micronutrients,
not to mention high-quality protein and fat.
KM: A recent study of factors associated
with inadequate childhood growth, size, and health in several third-world
nations identified inadequate amounts of particular micronutrients including
iron, zinc, calcium, and vitamin B12, rather than an inadequate supply
of protein or particular amino acids, as the likely culprits.
KM: Due to their content of available minerals
and vitamins, animal foods were recommended to help improve the nutritional
status of such children.
KM: If the evolutionary trajectory I have
hypothesized was characteristic of human ancestors, the routine inclusion
of animal foods in the diets of weaned children seems mandatory. Plant
foods selected largely for energy content would not be capable of supplying
the essential micronutrients or protein children require for optimal mental
development and growth.
KM: Many anthropoids appear to regard invertebrates
as highly desirable foods and will heavily exploit them when possible.
KM: For example, Hamilton and coworkers
discussed two instances in which chacma baboons largely abandoned the
plant component of their diet for days to feed on insect outbreaks. Ayres
reported that red howler monkeys in Brazil focused on eating caterpillars
when a huge number of them occurred in their forested environment (personal
communication). These and other accounts suggest that many anthropoid
species like invertebrates and will eat more of them when they can.
KM: As noted, some chimpanzees commit a
fair degree of daily foraging time to termite fishing and ant dipping.
KM: Such foods may, however, provide apes with
particular essential nutrients that are inadequately supplied by their
particular plant-based diets.
KM: Their summary indicates that meat-eating
is not a common feature of Old World anthropoid dietary behavior.
KM: One exception is the hunting behavior
of some common chimpanzees. Stanford reports that during peak periods
of meat eating by chimpanzees at Gombe, some adult male hunters may ingest
as much as 500 g of meat per week - a substantial amount. To date, factors
contributing to the hunting behavior of chimpanzees are not well understood,
but it has been suggested that social factors may be more important than
nutritional ones. One key point is that chimpanzees at Gombe rarely appear
to set out with the intention of hunting, but typically attacked prey
when they fortuitously encounter it during routine foraging excursions.
KM: Given the postulated body and brain
size of the earliest humans and the anatomy and kinetic characteristics
of the extant hominoid gut, the most expedient dietary avenue open to
proto-humans seems to have been to turn increasingly to the intentional
consumption of animal matter on a routine rather than a fortuitous basis.
KM: Early humans might have been able to
transform a lower-quality plant food into a higher-quality one through
technological innovations such as grinding or cooking.
KM: ... it seems most expedient to view
the earliest humans (Homo) as initially having turned to animal prey to
supply the amino acids and many micronutrients they required, using plant
foods primarily as an energy source.
KM: Future paleontological and archaeological
research, together with closer examination of features of comparative
gut anatomy and digestive physiology of Hominoidea and other anthropoids
should help to clarify the costs and benefits that were involved in the
adaptation of this dietary strategy in the human lineage and to determine
how this strategy may initially have been implemented. If the evolutionary
trajectory I have hypothesized was characteristic of human ancestors,
the routine inclusion of animal foods in the diets of weaned children
has caused this profoundly muddled thinking?
----- Original Message -----
Look--if you're so smart you teach here and
I'll retire and eat
So, she thinks
John's ongoing efforts in personally experiencing a totally raw, frugivorous-ape
diet, such as our species evolved on, is "odd", while her
mindlessly following of the local pathogenic, cultural, cooked-meat diet
is superior? Apparently, she does not understand cultural anthropology
sufficiently to realize that her narrow-minded acceptance of a totally-unnatural
meat-based diet was simply programmed into her at a very early age, without
her understanding, conscious analysis or decision, by similarly-programmed
and similarly-ignorant parents.
So, KM gets an "A" in the creative writing of fiction and academic arrogance, but an "F" in science, open-mindedness, communication, and human relations.