Creating Access to Reference Collections

Historic England zooarchaeologists, photographers and graphic designers are working together to produce a photographic atlas of perinatal animal bones, that is to say the remains of unborn (foetal), newly born (neonatal) and very young animals. This unparalleled resource will provide a key identification aid for distinguishing between the different species commonly found on archaeological sites in the UK and beyond, widening our understanding of past lifeways. The atlas builds and expands on the rare diagnostic resources currently available (for example Prummel 1987a, 1987b, 1988; Powell nd).

Making use of high resolution photography to highlight differences in shape and morphological detail between species, the resource will serve researchers in zooarchaeology, human osteology, forensics and zoology, fields in which comparative anatomy is central to scientific practice.

Zooarchaeology (the study of animal bones from archaeological sites) is extremely active across the globe, with the International Council for Archaeozoology (ICAZ) including over 500 members from 50 countries. In the UK alone the Professional Zooarchaeology Group (PZG) counts over 100 members working in the commercial, academic and public sectors, but there are comparatively few reference collections that include bones of perinatal animals either nationally or internationally. The atlas will provide virtual access to these important assets, the majority of which are held within the Historic England Zooarchaeology Reference Collection. The photographic atlas will be available to purchase as a high quality manual or to download from the Historic England website.

Archaeological applications

Accurate identification of the remains of very young animals can lead to interpretation of site use and further inform us on how past populations were influenced by, and responded to, their environment. Foetal and perinatal animal bones can be key indicators of seasonality, husbandry and hunting practices on archaeological sites, as natural gestation and birthing cycles in wild and domestic animals are controlled by physiological responses to daylight, weather and climate. Prior to modern husbandry methods, lambing, calving and farrowing (pigs) followed seasonal farming calendars. For example, in England lambing took place in late winter and spring. Gestation and birth are risky times for both mothers and babies and natural deaths may occur throughout this period.

At the Roman shrine of Great Chesterford in Essex, lambs were an important offering for animal sacrifice as evidenced by large bone deposits (Baxter 2011). Assuming traditional scheduling of births in April, in the first and second centuries lambs were selected in mid-spring when newborn to 1 month old, in summer at about 2-3 months of age, and at 9-11 months in winter and early spring. In the 3rd century AD this shifted almost exclusively to summer sacrifice.  The age distributions may reflect changing ritual cycles and seasonal availability of livestock, such as natural casualties around the time of birth and culling of surplus animals not required to replenish flocks, including very young lambs in spring and summer and older animals fattened prior to winter slaughter.

The identification of foetal horse remains has provided novel insight into prehistoric horse ‘ranching’. Horses formed part of the wild native fauna in the United Kingdom, but a recent review of radiocarbon dated remains suggests they disappear from the archaeological record in the early post glacial period, probably in the second half of the ninth millennium cal BC, the early Mesolithic (P Marshall pers comm). They were re-introduced in the 15th to 13th centuries cal BC, in the Middle Bronze Age (Andrews et al 2019). Their scarcity in archaeological assemblages in the Bronze Age and deposition in burials in the Iron Age may indicate their special status at this time (Bendrey et al 2013). Where preserved, the presence of perinatal horses in prehistoric sites may indicate controlled breeding of these valuable animals (Bendrey 2010).

Radiocarbon dating and genetic analysis of neonatal kittens in Iron Age sites, such as Danebury, Hampshire and Gussage All Saints, Dorset, as well as Fishbourne Roman Palace, West Sussex are being undertaken to improve our understanding of when domestic cats first appeared in Britain (Jamieson 2017). The newborn kittens will provide important information about wild and domestic cat biogeography and domestication processes. For example, while the domestic cat descends from the non-native subspecies, Felis silvestris lybica, crossbreeding may occur with the native European wild cat, F. s. silvestris, and deliberate or opportunistic feeding and raising of wild young kittens by humans may potentially lead to increasing familiarity and taming (Ottoni 2017; Sykes 2017).

Developing photographic techniques

Foetal and perinatal bone has a high collagen (organic) to mineral content and a porous and unstructured surface texture compared to adult bones. Morphology (the shape) and surface texture are key to recognising bones of these very young animals.

Standard elevations (views) were captured for each bone in a consistent manner to allow the user to easily compare shape, size and distinguishing features between and within species.

Creating standardisation in image structure, composition and lighting for recording animal bones has a similar set of requirements to architectural approaches, for example those of Bernd and Hilla Becher for industrial structures. These are not without challenges: the variation in bone size, their morphology, lighting and positioning, all pose difficulties in maintaining a consistent approach.

It is important that a standard methodology is applied to each bone element. For example with a humerus, four main elevations of each bone are shot first, followed by the ends (distal and proximal) and any other angles required to show diagnostic features. Both minute degrees of change in lighting angle and position of bone are critical, with finished results being the culmination of honing this pairing.

Lighting is crucial in illustrating the diagnostics and form of each elevation.

Lighting is achieved with two, sometimes three lights and the use of honeycomb grids to allow for control and reduction of light spill. Both camera and bone lie level and the use of spirit levels on both horizontal and vertical planes is set as standard. Handling bones that may only be 10 millimetres long and a few millimetres wide has its own set of problems and can be a painstaking business. A shallow tray filled with sand and covered in low-reflective black velvet allows for a certain level of flexible positioning with label and scales added, set at the mean height of each elevation

Correct lighting is required to render and understand the intricate morphology and surface structure of the bones, shown here by the photography of a pig mandible with (a) single flash on camera (b) three point grid lighting arrangement.

The images are shot with camera tethered to a laptop in a dehumidified studio where white walls have been covered with black to reduce reflection, and finally, with photographer wearing dark grey to minimize any cross colour contamination. All this is required in order to produce a systematic record of each bone, sufficient to ensure that all diagnostic features are revealed clearly and consistently.

The images are processed in camera raw with further adjustments in Adobe Photoshop. The processed views are then ‘cut out’, removing the velvet background and replacing with dense black, scaled and assembled in a four to six view standard layout.

Preparing specimens for photography

Most of the specimens in the Historic England collection and loans had been prepared following similar standard procedures (Davis and Payne 1992) and were ready for photography. All bones were labelled with their unique accession code, usually a number, to ensure that their identity and source collection could be verified throughout the process. Labelling tiny, porous bones is a challenge, with numbers sometimes only 1milimetre in height!

Bringing together a range of skills

The production of the atlas utilised a range of skills available within Historic England. Zooarchaeological understanding of morphology, species identification and discipline standards are required to ensure valid and comparable photographs, and accompanying text, but the imagery is at the forefront of the atlas and technical photography and graphic design skills are essential in its production.

Acknowledgements

Eva Fairnell prepared, cleaned and labelled multiple specimens used in the atlas. Many individuals and institutions kindly loaned perinatal specimens for photography and study, including Angelos Hadjikoumis and Umberto Albarella (University of Sheffield), Sheila Hamilton-Dyer, David Orton (University of York), Dale Serjeantson and Jaco Weinstock (University of Southampton) and Sue Stallibrass (University of Liverpool). Adrienne Powell provided access to her unpublished work on juvenile cattle and red deer. Professional Zooarchaeology Group members who attended the meeting on perinatal animal bones generously contributed their feedback on diagnostic criteria. Vicky Crosby kindly provided the archive image of the Stanwick excavation. Peter Marshall provided advice regarding latest Radiocarbon evidence for horses in the UK.

About the authors

Further information

Andrews, P, Last, J, Osgood R, and Stoodley N, 2019: A Prehistoric Burial Mound and Anglo-Saxon Cemetery at Barrow Clump, Salisbury Plain, Wiltshire English Heritage and Operation Nightingale excavations 2003−14. Wessex Archaeology Monograph 40. Salisbury: Wessex Archaeology

Baxter, I 2011 ‘Faunal Remains. Temple Precinct’, in Medlycott, M (ed) The Roman Town of Great Chesterford. East Anglian Archaeology 137, 320-344

Bendrey, R 2010 ‘The horse’, in O’Connor T and Sykes, N (eds) Introductions and Extinctions. A Social History of British Fauna. Oxford: Windgather Press, 11-16

Bendrey, R, Thorpe, N, Outram, A, and van WijngaardenBakker, L H 2013 ‘The Origins of domestic horses in Northwest Europe: new direct dates on the horses of Newgrange, Ireland’. Proceedings of the Prehistoric Society, 79, 91-103. doi:10.1017/ppr.2013.

Davis, S and Payne S 1992 ‘101 ways to prepare a dead hedgehog: notes on the preparation of disarticulated skeletons for zoo-archaeological use’. Circaea 8(2), 95-104

Jamieson A 2017 ‘When Did Cats arrive in Britain?’ University of Oxford (Oxford Sparks)

 Ottoni, C et al 2017 ‘The palaeogenetics of cat dispersal in the ancient world’. Nature Ecology & Evolution 1, 0139 (2017). doi: 10.1038/s41559-017-0139

Powell, A nd ‘Criteria for distinguishing between perinatal bones of cattle and red deer’. Unpublished document

Prummel, W, 1987a ‘Atlas for identification of foetal skeletal elements of Cattle, Horse, Sheep and Pig, Part I’. Archaezoologia, I(1), 23-30

Prummel, W, 1987b ‘Atlas for identification of foetal skeletal elements of Cattle, Horse, Sheep and Pig, Part 2’. Archaezoologia, I(2), 11-42

Prummel, W, 1988 ‘Atlas for identification of foetal skeletal elements of Cattle, Horse, Sheep and Pig, Part 3’. Archaezoologia, II(1, 2), 13-26

Sykes, N 2017 ‘Local and Exotic’. Paper presented at Retrospect and Prospect: 50 Years of Britannia and the State of Romano-British Archaeology, Nov 17, 2017. Senate House, London.

Download PDF magazine

You can download this article in PDF format as part of Historic England Research magazine Issue 16.