Zooarchaeology Final Exam

Taphonomy is

Taphonomy is

The study of fossil assemblage formation

Raymond Dart was

one of first to start to wonder about how the bones he was recovering arrived there in the first place

osteodontokeratic industry - means they thought that

they were using heads, teeth, and hooves in tool manufacture

Dart’s Australopithecus research

- noticed damage to Australopithecus cranium – previously thought it was evidence of cannibalism

- puncture marks on skulls line up really well with teeth of a cheetah

- Brain thought it might be big cats creating these assemblages

Taphonomic factors that are not controllable

• natural factors influence bone population

• cultural practices influence bone population

• primary and secondary disposal can lead to bone loss, population is decreased

• tertiary deposition and differential preservation decrease the bone population

Taphonomic factors controlled by archaeologist

• area chosen for excavation

• recovery methods

• analytical methods

• publication

Catastrophic death assemblage

- “snapshot of population

largest proportion of the population was young individuals

- younger individuals are less likely to preserve

-humans can create either catastrophic or attritional

Attritional Death Assemblage

- vulnerable groups (young and old) are best represented

- individuals being picked off one by one over a longer period of time – attritional death assemblage

- low intensity disease may do the same thing

- natural death will often look like this too

-death from hunting by predators looks like this

Equifinality

– idea that there are many different ways to arrive at the same pattern (in archaeological record in this instance)

Diagenesis

breakdown of bone, specifically weathering

- bone dries out and bleaches, starts to crack,

- scale determine the level of weathering

Burial environments where is it hard to find bones

acidic soils, warm temperature, moisture in the boreal forest

Post burial transformation

•Certain species/individuals/elements more subject to destructive processes than others

Erlandson Taphonomy example

• studied a historic bald eagle nest

• archaeologists working on sites in coastal, riverine, or lacustrine settings should consider the possibility of non-cultural origins of marine or aquatic faunal remains and their potential association with archaeological materials

• bald eagles are active transporters and accumulators of bones from marine and aquatic fauna

• differentiate natural from cultural accumulations of faunal remains

How do archaeologists influence the faunal assemblage during recovery?

- excavation

- flotation

- doing something different or more specific to screen adds more time to the process

- choice of excavation area

- method of excavation

- screening (all, some, screen size, dry or wet)

- experience of screener and excavator

What is flotation for?

- In flotation, archaeological material is really tiny, majority of items are not identifiable beyond class (fish, mammal, bird)

- can be valuable if there’s a lot of fish bone or something, really tiny bones identifiable to taxon in fish

Element based approach to recording

each element recorded independently

Context based approach to recording

elements from the same archaeological context recorded collectively

Shaffer recovery, processing, identification, recording example

• Fine screening is time consuming and expensive

• ¼” screens are standard

• this size screen has a bias for larger specimens

• recovery and loss of specific taxa can be predicted

• Mammals with weights of less than 140g are lost

• Specimens weighing from 71 to 340g are poorly represented

• specimens weighing from 340 to 3,100g are represented by most elements except foot bones

• Taxa greater than 4,500g are represented by most elements.

NISP stands for

Number of Identified Specimens

MNI stands for

Minimum Number of Individuals

NISP is the:

Count of all “specimens” identified to taxon

A “specimen” is

a bone, tooth, antler or horn, or part thereof

Strengths of NISP

•Easy to calculate

•Additive

•Always calculated the same way – ensures comparability

Weaknesses of NISP

NISP ǂ dietary importance

•Affected by sample size

•Affected by butchery and transport

•Affected by fragmentation

•Affected by identifiability

example of NISP calculation

Strengths of MNI

Less affected by fragmentation, butchery & transport, and identifiability than NISP

Weaknesses of MNI

•Derived from NISP and ultimately shares all of its weaknesses (esp. sample size)

•MNI ǂ dietary importance

•Different calculations means not always comparable between sites

•Tends to over-represent rare taxa

•NOT additive

•Problem of aggregation

MNI and NISP together

• often used together

• real number of individuals lies somewhere between the two

• Best understood as ORDINAL rather than ABSOLUTE measures

MNE Stands for

Minimum Number of Elements

MAU stands for

Minimum Animal Units

MNE is

Minimum number of complete elements that could account for all the specimens of that element

MNE example

MNE is 5

MAU is

MNE divided by the number of that element in one complete skeleton

Allows a direct comparison between skeletal elements

Factors affecting MAU and MNE

• affected by sample size

• affected by fragmentation and identifiability

• not additive

• is affected by problem of aggregation

• MAU is based on MNE

• probably not going to be affected differently

Reconstructing environmental change can be done with

Indicator Species – limited environmental tolerances

What are assumptions we make when reconstructing environmental change

environmental tolerances that we know from the present are probably the same from the past

Population changes as we move away from the equator

diversity decreased, larger populations with less species

Population diversity in the arctic

number of possible species that a fragment could be is small

Reconstructing human impact on the environment

- moving towards more jackrabbits than cottontails

- cottontails being hunted

R-Selected species

reproduce very quickly, a lot of offspring and short breeding period, rabbits

K-Selected species

opposite, reproduce slowly, less offspring and longer breeding period

Badenhorst and Driver species representation example

changing animal usage over time in the San Juan Basin

• artiodactyls declined over time in relation to lagomorphs

• Turkeys increased in the northern regions when compared to lagomorphs. Cottontails increased when compared to jackrabbits over time

• as human populations increased in the San Juan Basin, artiodactyls were more intensely hunted

• then began to raise more turkeys in favorable regions, and also hunted more lagomorphs in relation to artiodactyls

• deforestation - better environment for cottontails

Butchery and transport example

- they’re not taking the entire animal

- partial remains because they’re butchering the animals and bringing a lot of ribs back

- or maybe someone else down on the plains is hunting, these parts are arriving up in the mountains via trade

- might not be able to figure out which one it is just from the bone

• equifinality

how do we quantify utility

We usually quantify utility in terms of food (meat, marrow, grease

Other factors also play into transport decisions:

     e.g. tool raw materials, architectural value 

Utility indices

Not just for meat

General Utility Index (GUI)

 “Modified” utility indices to account for “riders

Camp site

not a lot of low utility items, a lot of high utility items (food and stuff)

Kill site

a lot of low utility items, not a lot of high utility items

Hoffman butchery and transport example

• salmon processing and storage

• a lot of cranium in the camp site – they’re beheading them and bringing the rest back to the village

What methods can we use to determine season of death?

- if we know when it died we can work out how old it was

- what season it was born in

- what season it died in

Common assumptions when determining seasonality

species of the past had the same migratory ranges at the same time of year

challenge – people store food, people could have brought stored resources to sites- Does seasonal species always mean occupation at that time?

Seasonal structures on an animal are:

things that are only present on animals at certain times of year – antlers

Incremental growth structures are

In seasonal environments many tissues alternate rapid growth with slow growth

Visible in thin-section – development of most recent growth layer indicates season of death

IGL stands for

incremental growth layers

GLG stands for

Growth layer group (once per year)

Tooth eruption and seasonality

•In species with a restricted birth season, dental eruption can be used to estimate season of death

•Requires young individuals in early stages of development (aging becomes imprecise for older individuals)

Seasonality and birth patterns

•In species with a restricted birth season, at any moment in time there are discrete age cohorts in the population

•In a seasonally hunted population, body size of young individuals will cluster for each age cohort

•A population hunted year-round will display a continuous size distribution

Juvenile populations importance to seasonality

In many cases, seasonality information can only be gleaned from the juvenile individuals in a population:

•Tooth eruption

•Growth (bone measurement data)

•Incremental growth structures also easier to read in younger individuals

Landon 2008 Seasonality example

• 17th and 18th century - Chesapeake bay area had seasonal hunting patterns

• looking at seasonal slaughter patterns helps us see the connection between town and country through the urban food supply system

• can look at culture too

Factors indicating domestication

• animals get generally smaller

• Shift in relative abundance of species over time

How are age cohorts formed in a population

Some animals give birth at a restricted time of the year

Population that was killed in a moment of time – you can pick out age cohorts

methods for Sexing species

–Sexual structures

–Morphological differences

–Dimorphism

methods for aging species

–Tooth-sectioning

–Epiphyseal fusion

–Tooth eruption

–Tooth wear

-growth

Herd management and domestication

•Among farming groups, population structure (age and sex) tells us about herd management strategies

Meat culling mortality profile

• less steep than other mortality profiles

• some reason for males to reach adulthood - meat

milk culling mortality profile

-If you just want milk, there’s no reason for males to reach adult size, really steep population drop

Wool culling mortality profile

-Male sheep can be used for wool

-Less deliberate culling of males

-Only big drop is infant mortality

Payne prey selection and domestication example

• describes a method for recording prey selection data for sheep and goats

• use mandibles and mandibular teeth

• using the relative representation of different age-groups in a sample

Behavioural ecology is

A branch of evolutionary ecology

Evolutionary ecology also looks at the ecological context of adaptation

     - Emphasizes use of models to predict and analyze

When evolutionary ecology is used to examine the behaviour of humans and other animals, it is called behavioural ecology

Studying cultural adaptation through B.E. can be difficult because the rate of change is much faster than for biological traits

Neo-Darwinian

differential reproduction is the main force shaping biological adaptation.

Fitness measured by number of offspring.

Behavioural ecology studies evolution at the ( ) level

phenotypic

→ Genotypes – genetic makeup

→ Phenotypes – how genetic makeup is expressed

Sees behaviour as adaptive and part of the phenotype

Underlying assumptions of behavioural ecology

People will always choose to “optimize” their food procurement strategies

They calculate costs and benefits and make rational choices to maximize food returns

Patch model choices

applies when resources occur in clusters (or patches)

foragers can affect their overall return rates by spending more time in these patches

Optimizing prey choices

CURRENCY: calories

CONSIDER:

1) Gross calories per animal

2) Cost of procuring animal (time and energy)

3) Abundance of animal (encounter rate)

Central Place Foraging Model

Assumption: People prefer to hunt close to home, will move farther afield as resource becomes less available

Hunting close to home: Bring back whole animals

Hunting farther afield: Preferential selection of high utility elements

Transport costs – more selective about transport as transport costs increase

Rate of Prey Encounter effects

Hunters move to lower ranked prey as encounter rate of higher ranked prey decreases

Starkovitch evolutionary ecology example

• prey choice, central place foraging, and patch model models applied

• Middle Paleolithic hominins focused on high-ranked large game resources, while Upper Paleolithic and Mesolithic occupants shifted to lower ranked small game, fast-moving animals

• unique environmental and cultural circumstances are reflected

Hawkes’ Ladder of Inference

religious/spiritual life

social/political institutions

subsistence-economics

techniques of production

Example of social status and animal remains

Major cuts of beef ranked according to late 19th century retail values

Components of social identity affecting access and use of food resources

community, ethnicity, status, wealth, religion, gender, age etc

After non-human taphonomic factors are ruled out, zooarchaeological evidence often reveals socially driven differences within and between sites in terms of:

•abundance, diversity and evenness in the representation of taxa

•relative abundance of skeletal parts for a given taxon

Important assumptions/shortfalls of social status and zooarchaeology

We need to rule out other explanations for the observed patterns (such as environmental differences that impact local availability of taxa)

•While it can be difficult to know exactly how the different aspects of identity contributed to the observed patterns, the most convincing explanations are supported by multiple lines of evidence.

Valenzuela Lamas Social Status and Zooarch example

• The combination of several criteria regarding the presence of species, the skeletal part representation and the butchery pattern, converge towards a Jewish origin of the faunal remains

• These two assemblages constitute one of the few opportunities for characterizing the diet of the Medieval Jewish communities in Spain, and for comparing it to contemporary Muslim and Christian populations.

• use the animal remains on site and kosher laws to determine if Jewish people were there