Title: You are what you eat!
1You 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
2Homo erectus
- Glacial conditions
- Cave / sapling shelters
- Fire
- warmth
- protection
- cooking?
3Chimpanzee 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?
4Chimpanzees 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
5Australopithecines
- 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)
6Australopithecines 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)
7Australopithecines 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)
8Australopithecines 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)
9Australopithecines 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
10Australopithecines 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)
11Early 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
12Paranthropus 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?
13Did 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
14Zhoukoudian (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?
15Zhoukoudian (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
16Zhoukoudian (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
17But,
- 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?
18Brain 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
19Mass-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
20Organ 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
21Dietary 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
22How 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
23How 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
24How 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
25How 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
26Cannibalism
- 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
27Cannibalism
- 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
28Cannibalism
- 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
29Conclusion
- 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