You are what you eat!

1
You are what you eat!
The headhunter is not content merely to possess
the skull, but opens it and takes out the brain,
which he eats in order by this means to acquire
the wisdom and skill of his foe GHR von
Koenigswald Diet underlies many of the
behavioural and ecological differences that
separate species, and so is important in defining
niche, with all its implications for the ecology
and evolution of extinct forms Peter Ungar, 2003
Dr. Susannah Thorpe, Rm W126 Email
S.K.Thorpe_at_bham.ac.uk
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Homo erectus

• Glacial conditions
• Cave / sapling shelters
• Fire
• warmth
• protection
• cooking?

3
Chimpanzee diet

• Fruit, insects, leaves, bark, meat (monkeys,
  pigs, small antelope)

• Hunting mostly males, cooperative specific
  roles
• Gombe ca.150 red colobus monkeys killed during
  peak hunting year
• Peak male chimp meat consumption near lower end
  of human consumption (5-10 of diet)
• Excited by meat, crave it, chew it long and
  thoughtfully, usually with a mouthful of leaves
  added
• Social event shared between hunters/ kin/ allies
• Infanticide- Banana provisioning?

4
Chimpanzees medicinal plants

• Medicinal plants pith or leaves of plants with
  medicinal properties
• know when they need it
• knowledge to select particular species that are
  not part of normal diet
• Tongwa people eat the same plants for medicinal
  use
• unpalatable, chimps swallow them like pills
  rather than chewing the leaves
• Contain an antibiotic against bacteria, viruses,
  fungi and parasitic worms

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Australopithecines

• Tooth shape evolves to improve mechanical
  efficiency for chewing . - tooth morphology
  differs among species adapted to different diets
• Teeth dominate fossil hominin assemblages
• Fossil hominin teeth generally very worn, - cant
  use standard measures for measuring cusp shape

• Afarensis (top)
• H. erectus (bottom)

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Australopithecines Topographic analysis

• Laser scanner - generate 3D points along the
  surface of a tooth
• Geographic information system (GIS) - model and
  characterize the surface points
• Score teeth by wear stage - compare shape data
  among similarly worn specimens of different
  species

(Unger 2004)
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Australopithecines Topographic analysis

• Occlusal relief
• high (h)
• low (l)
• Cusp shape
• sharp (s)
• round (r)
• blunt (b)

• ? occlusal relief and steeper cusps ? efficiency
  in fracturing tougher, more deformable foods
  (leaves)
• ? occlusal relief and ? steep cusps ? efficiency
  in fracturing brittle, less deformable foods
  (nuts/seeds/hard fruits)

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Australopithecines Topographic analysis
A gorilla B chimp C early Homo D A. afarensis

• Gorilla gorilla have the steepest slopes and most
  relief ? early Homo ? Pan troglodytes ? A.
  afarensis which has the flattest slopes with the
  least relief

(Ungar 2004)
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Australopithecines Topographic analysis

• Dental morphology reflects adaptations to primary
  foods, and also to less frequently eaten but
  still critical ones
• Gorillas ? occlusal relief and steeper cusps ?
  efficiency in fracturing tougher, more deformable
  foods (leaves)
• Both prefer soft fruits but gorillas can take
  advantage of fallback foods that are less
  accessible to chimps

A gorilla, B chimp
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Australopithecines Topographic analysis

• A. afarensis- ? crown relief and ? sloping
  occlusal surfaces than gorillas or chimps
• more efficient fracture of brittle, less
  deformable foods but less efficient fracture of
  tough, more deformable foods
• ? preferred soft, sugar-rich fruits, but would
  have been able to make better use of hard,
  brittle resources as fallback foods given
  seasonal availability
• of favored items

Gorilla gorilla (A) Pan troglodytes (B) Early
Homo (c) A. afarensis (D)
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Early Homo Topographic analysis

• Early Homo intermediate bw chimps gorillas in
  slope and occlusal relief, ? intermediate in the
  fracture properties of the foods to which it was
  adapted
• ? ? efficiency in fracturing tough, pliant foods
  than chimps or A. afarensis
• thinner enamel sharp edges at sites of dentin
  exposure with wear would improve shredding and
  slicing efficiency
• What tough foods were available to early Homo?
• Meat tough and elastic. gt occlusal relief and
  steeper sloped cusps yield sharper cutting
  surfaces reduces meats ability to stretch and
  absorb energy, ? thwarts major toughening
  mechanism

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Paranthropus boisei

• Ungar A. africanus Paranthropus lived at
  different times at Sterkfontein
• A. Africanus steeper molar cusps
• Paranthropus large, crushing teeth (roots/seeds)
• Did climatic swings lead to reduction in food
  sources for Paranthropus?

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Did H. erectus hunt or scavenge?

• more food per square mile of the African savannah
  than plant food
• more effective energy source
• venison 572 cals per 100g
• fruit/veg lt100 cals per 100g
• Reduced risk of seasonality, esp. in Northern
  temperate zones

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Zhoukoudian (China), 400,000ya Peking man
Ash, choppers, flake tools fossilised remains
of H. erectus Cosy domestic scene, with H.
erectus using fire for warmth, protection and to
cook meat Did fire played a regular or
important role in the daily life of the
inhabitants?
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Zhoukoudian (China), 400,000ya Peking man

• Certainly some evidence of fire, but Lewis
  Binford
• Many of the extensive ash layers may be results
  of the decalcification of massive organic
  deposits (including bird droppings, bat guana,
  hyena faeces)
• Fires could have been a result of the accidental
  ignition of the organic material, which then
  smouldered for some time
• Binford found no hearths, or any association
  between ash, stone tools and H. erectus fossils
• So although had all the ingredients of a cosy
  domestic scene the ingredients were not related

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Zhoukoudian (China), 400,000ya Peking man

• Little evidence of cooking food. A few burnt
  bones (2 roasted horses heads), but other burnt
  bones had been meatless when put in the fire ?
  caught up in smouldering organic material
• Binford et al
• hyenas responsible for most of the materials in
  the cave
• H. erectus scavenged from hyenas (hyena gnaw
  marks underneath hominid stone tool cut marks on
  some bones)

a
b
a hyena, b stone tools
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But,

• Stone tool evidence
• Schick Toth wear patterns experimental
  studies -Acheulean hand axes cleavers were used
  for extensive meat eating
• Anatomy (size and shape) Alan walker
• H. erectus
• comparable to top 17 of modern human pop. in
  height and mass
• anatomical stasis (early forms very similar to
  late forms)
• ca.1/3rd larger than H habilis and H rudolfensis
• Could scavenging really have brought about a
  change of this magnitude?

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Brain size vs. gastrointestinal tract

• H. erectus 27-62 increase in brain size
  compared to early H
• Earlier species had funnel shaped rib cages and
  pot bellies like living apes
• H. erectus probably first hominid type to show
  a barrel-shaped thorax and a distinct waist
  similar to modern humans
• significant decrease in size of gastrointestinal
  tract

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Mass-specific organ metabolic rates in humans
Organ Metabolic weight in W. Kg-1 (watts per kg)
Brain 11.2
Heart 32.2
Kidney 23.3
Liver gastro-intestinal tract 12.2
Skeletal muscle 0.5
Lung 6.7
Skin 0.3

• Brain mass specific metabolic rate c.9x average
  rate for body
• Liver/gastrointestinal tract mass specific
  metabolic rate c.9.8x average rate for body
• 2 ways to accommodate the increased energy
  demands of the large brain of HE
• raise the overall basal metabolism rate of the
  body or
• compensate for brain growth by reducing the size
  of another metabolically expensive organ

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Organ weights
Observed human organ weights in comparison to
expected weights for a mammal our size
Humans same standard basal metabolism rate for
mammals our size but we have much bigger brains
and smaller gastrointestinal tracts than
expected The energetic savings from reducing the
digestive system c. added cost of larger
brain ? beginning w. HE, humans experienced an
evolutionary trade off of intestines for brains
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Dietary implications
Food quality Food quantity/ processing time Intestinal requirements
poor quality (low energy) / hard-to-digest (e.g. gorillas) eat a lot process it slowly large stomach and intestines
high quality (high energy) / more digestible diets (e.g. carnivores) less food smaller organs for digesting it

• By hunting H. erectus accessed energy rich food
  source
• Only hunting would have provided enough
  consistent protein for this to take place
• Surplus energy was used to feed hominin brains,
  which began to grow significantly

Meat eating
Brain enlargement
clever ways to obtain more meat
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How did they hunt?

• Methods to study early hominin behaviour

A Living system in the present
D Living system in the past
A Kalahari hunter gatherer Behaviour
(ethnographic observation)
D Prehistoric hunter gatherer behaviour
(archaeological observation)
B Contemporary fossil record
C Fossil record
B Material and organic debris of hunters and
gatherers
C Archaeological record (excavation)
Analogue from present to past
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How did they hunt?

• African hare quick but vulnerable
• when the hare is about to dodge, it lays its ears
  all the way back
• seeing this hunter veers L or R (50 chance of
  being right)
• if hunter guessed wrong, the hare will usually
  run for cover and stay there without moving
• primates highly developed colour vision will see
  through the camouflage

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How did they hunt?...persistence hunting

• Insight into animal behaviour e.g. antelopes and
  gazelles move in an arc when trying to escape
• key persistence, keep it in constant motion
  until exhaustion
• Tarahumara Indians of Mexico pursued a deer for
  2 days. Never loose track of its spoor
• Supported by H. erectus anatomy
• Barrel shaped rib cages ? high levels of
  sustained activity. Ventilation of the lungs
  enhanced by the ability to raise the upper part
  of the rib cage (enlarging the thorax) when
  taking deep breaths
• Waist allows upper body to twist at the abdomen
  and arms to swing freely stabilises upper body
  in B. running
• Human leg muscles capable of producing large
  forces

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How did they hunt?... stalking, driving ambush

• Chimps do it
• Torralba and Ambrona (Spain, 400kya, Acheulean)?
  H. erectus hunters driving elephants, horses,
  deer rhinos into marshy bogs, killing them
  butchering them
• Reanalysis (Klein Shipman 1980s) ?hominins (H.
  erectus/ heidelbergensis) used some of the
  carcasses (cut marks), no conclusive evidence of
  actual hunting
• ? scavenging the remains of animals that had died
  naturally or killed by carnivores

• 1st confirmed driving/ambush ? La Cotte de St.
  Brelade (Jersey) mammoth and rhino drives
  (240kya-125,kya). H. heidelbergensis

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Cannibalism

• Zoukoudian human skulls faceless had been
  opened at the base

• ? cannibalism - eating the brains of the dead
• a lack of humanity or culture (spiritual
  notion that cannibalism could increase their
  powers)
• cannibalism in recent times the act is nearly
  always carried out as a ritual not for food
• Distinction between dietary and ritual
  cannibalism extremely important its very rare
  for people to eat other people merely for food

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Cannibalism

• but,
• Lewis Binford hominin remains are found in
  deposits containing many other bone fragments,
  including numerous predators (e.g. Chinese hyena)
• The removal of the faces/ destruction of the
  skull base what happens when gnawing carnivores
  chew out the face of their prey
• Fossils disappeared in WWII

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Cannibalism

• Middle awash in Ethiopia (Tim White)
• curious marks on the skull of H. erectus
  forehead of the individual and around and inside
  the left eye socket
• ? scalping removing tissue from the face
• Why would another hominid have done such a thing?
  
• Whether it remains cannibalism, head hunting, or
  some other behaviour remains a mystery at present
• Indicates developed culture

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Conclusion

• Nomadic - following migrating herds problems
  transporting food and water

• No direct evidence
• ? bags made of animal hides containers made of
  wood, leaves, clay?
• Material for toolmaking - probably transported,
  tools often made at the butchery site
• Cooler climates may have stimulated the
  control/use of fire and the construction of
  clothing (animal pelts, e.g. Terra Amata bedding)

• All these behaviours can be related to meat
  eating
• Put an even higher premium on continued and
  better access to meat