Animal, mineral or vegetable (or sorting the sheep from the goats)
Environmental archaeology and zooarchaeology are the two sub-disciplines that tell us most about the physical habitat in which past people lived.
Did they live in a forest? Open fields? Through a time of drought? Was it originally a wet climate, or under water? Cold or warm overall? What sort of animals were kept? Were they wild or domesticated? How old or young were they when slaughtered, and what were they used for? And what other wild animals lived in the area?
All these questions, and many more, can be answered by careful study of the soil coming out of particular archaeological contexts.
'Enviro', as it's commonly called, is a highly specialised area where tiny finds can reveal enormous amounts. Soil samples are put through a flotation tank that allows the soil to drop away, and sieves retain the tiny particles of plant and animal matter that can answer some of these important questions.
Seeds, pollens, the microscopic shells of molluscs and tiny mammal and bird bones all tell their own story about how the land was shaped and used at the time the sample was sealed away. What has been done to them - eg. are the seeds burned, crushed or partly germinated - can tell us even more.
On a larger scale, animal bones - the study of zooarchaeology, or archaeozoology - give valuable information on farming practices, diets and local wildlife. Sorting out the bones and identifying the animals they originate from permits the calculation of important statistics like the Minimum Number of Individuals, or MNI. This figure in turn permits us to estimate the size of the herd or the farm, an estimation that then may shed light on the size of the local human population.
From these myriad tiny details, like detectives solving a crime, we build up an image of the settlement, village or other human occupation that we are studying.
Though some questions will always remain. For example - sheep or goat? The animals may look completely different in life, but their post-cranial (below the neck) skeletons are identical. Who would have thought?