An age profile is filtered through biology, preservation and method
Teeth can preserve growth and wear evidence long after other tissues disappear, but an archaeological age-at-death profile is not a direct life table. This guide shows how to separate observation, calibration and survivorship before reading husbandry or mortality from the pattern.
Choose a reading route
- Start from first principles — define the unit and the threat.
- Follow the worked example — make the hidden arithmetic visible.
- Test transfer — change the setting and preserve the rule.
- Audit the evidence — inspect records, assumptions and failure points.
- Use the practical checklist — apply the method to new work.
Chapter contents
Foundations: Chapters 1–3
Method: Chapters 4–6
Transfer and limits: Chapters 7–9
Connections and use: Chapters 10–12
1. Age-at-death is estimated, not read directly
Eruption, replacement, crown formation and wear change through life. Archaeologists convert these observations into stages or age ranges using reference sequences. Each conversion carries uncertainty because development and wear vary among taxa, populations, diets and individuals.
Report observed dental states before interpreted ages so another analyst can apply a different scheme.
First principle
Keep the biological observation, calibration rule and demographic interpretation as three separate layers.
2. Eruption and wear answer different parts of life
Tooth eruption and replacement are most informative for younger animals because developmental timing is directional. Wear continues through adulthood but depends on diet, grit, jaw mechanics and tooth loss. Very old individuals may lose the teeth needed for scoring.
| Indicator | Best information | Main limit |
|---|---|---|
| Eruption sequence | Juvenile development | Population timing varies |
| Crown height or wear | Adult relative age | Diet changes rate |
| Tooth loss | Advanced ageing clue | Disease and trauma intervene |
| Fusion data | Independent youth stages | Bone preservation differs |
Avoid converting a broad wear stage into a falsely precise calendar age.
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3. Survivorship is not the same as the excavated profile
A mortality profile begins with animals alive at risk, then passes through death, disposal, transport, preservation, recovery and identification. Juvenile bone may be fragile; old teeth may be lost before death; particular jaws may be selected for processing or craft.
- Define the assemblage formation context.
- Compare mandibles, maxillae and isolated teeth.
- Record ante-mortem tooth loss and unscorable surfaces.
- Check whether age classes preserve and recover differently.
An apparent shortage of young or old animals can be taphonomic as well as behavioural.
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4. Worked example: one assemblage, two calibrations
A fictional set of 80 sheep/goat mandibles is scored once. Under Calibration A, 18 are juvenile, 42 young adult and 20 older adult. Calibration B uses different wear-rate boundaries and classifies the same observations as 18 juvenile, 34 young adult and 28 older adult.
| Age class | Calibration A | Calibration B |
|---|---|---|
| Juvenile | 18 | 18 |
| Young adult | 42 | 34 |
| Older adult | 20 | 28 |
The proportion called older adult rises from 25% to 35%. A husbandry story should not depend on one boundary without sensitivity analysis.
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5. Standardise scoring before interpretation
Use illustrated landmarks, explicit tooth positions, left/right rules, eruption states and surface-preservation codes. Blind repeat scoring on a subset can reveal observer drift. Resolve disagreements before studying group differences.
| Record | Why it matters | Common failure |
|---|---|---|
| Tooth position | Stages are position-specific | Mixed molars |
| Surface visibility | Wear must be observable | Damaged teeth scored |
| Side and jaw | Avoid duplicate individuals | Loose teeth double counted |
| Scheme version | Calibration can change | Uncited categories |
Archive photographs for ambiguous and boundary cases where permissions allow.
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6. Link profile shape to competing hypotheses
A high proportion of young animals may fit meat production, mortality stress or selective disposal. Older animals may fit secondary products, breeding retention or preservation of robust jaws. State predictions for sex, pathologies, butchery, seasonality and context.
Use independent evidence to decide among explanations rather than letting the age curve carry the entire argument.
Practical check
Replot the profile under at least two plausible age schemes and with unscorable specimens shown, not hidden.
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7. Transfer test: human dental wear
Move the method to human remains. Molar wear may correlate with age, but diet, cultural food processing, tooth loss and population-specific wear rates affect the calibration. Older adults can become hard to age precisely when teeth are missing.
Transfer succeeds when the report uses broad, honest intervals, records ante-mortem loss and validates the method against appropriate known-age material where possible.
The same principle holds across species: a reference chart is evidence, not a universal clock.
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8. Misconceptions and limits
- “Tooth wear is chronological age.” It is an age-related process shaped by diet and population.
- “Teeth preserve, so the sample is unbiased.” Teeth and jaws still enter and leave assemblages selectively.
- “More age classes mean more precision.” Fine bins can exceed the method’s resolution.
- “One chart fits every period.” Wear rate and food processing can differ.
- “A mortality profile proves husbandry strategy.” Formation and recovery alternatives remain.
Age estimates should widen when evidence is sparse or contradictory, not narrow to make the narrative easier.
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9. Evidence audit
Audit specimen provenance, taxon, tooth position, eruption, wear, tooth loss, surface condition, observer, calibration, duplicate-control rules, recovery fraction and context integrity. Preserve the raw stage table alongside final bins.
| Audit question | Evidence | Warning sign |
|---|---|---|
| Can ages be recalculated? | Raw dental stages | Age bins only |
| Does calibration fit? | Reference population | Universal chart assumed |
| Are ages differentially missing? | Preservation by class | Unscorable ignored |
| Is context coherent? | Stratigraphy and taphonomy | Mixed deposits pooled |
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10. Questions readers often ask
Are isolated teeth useful?
Yes, but duplicate control and uncertain individual attribution must be explicit.
Should broad or narrow age classes be used?
Use the narrowest classes the evidence can support consistently, then test broader groupings.
Can wear and fusion be combined?
Yes, if their observations and uncertainties remain visible rather than collapsed into a single exact age.
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11. Reading routes and ecosystem connections
Begin with the Gold Standard of Education: learning that transfers into life, The Gold Standard and the How X Works hub. The subject foundation is the Gold Standard of Archaeology.
Continue with assemblage integrity and refitting, recovery fractions and mesh bias, MNI and aggregation bias, and taxonomic abundance and density-mediated attrition.
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12. Sources and practical checklist
Authoritative and primary references include Historic England’s Ageing the Old research, the open dataset paper An International, Open-Access Dataset of Dental Wear Patterns, and the professional standards for recording human remains.
- Record observable dental states first.
- Cite the calibration and version.
- Keep age ranges honest.
- Show unscorable and missing teeth.
- Test alternative bin boundaries.
- Audit preservation by age class.
- Use independent evidence for demographic claims.