ossamenta: A flock of sheep from a medieval manuscript (Sheep)
As part of my Ph.D. idea I'm exploring ways to identify castrated sheep from their bones. Castrates were very popular as wool producers, since they grew big and their fleeces weren't affected by hormonal changes from breeding. Medieval records from wool producing flocks show the presence of large numbers of ewes and castrates, but hardly any rams. So if you want to detect wool producing sheep flocks, you want many adult/older ewes and castrates.

I did a study on some sheep skeletons in Denmark many years ago, and wanted to do a follow-up on a different breed, just in case the traits I found on the Danish sheep were breed specific. So today was spent in the stores of English Heritage in Portsmouth, looking at many sheep skeletons. As expected, things weren't totally obvious, but a bit complicated. Still, when I did a blind test, I got almost all sheep correctly sexed. So there is certainly something about my method.

Now I need to put up my notes in a file and send them back to EH, as part of the deal to use their collection is the requirement that they get a record of what I did. And then sort out my next step on my research. It will involve lots of photos, and even more sheep skeletons...

Misc. links

Jul. 4th, 2012 07:21 pm
ossamenta: Weasel skull (Default)
I have re-surfaced after a really fun dance weekend, and while I am still very tired and have sore feet (it was so worth it!), there's no rest for the wicked (nor for anyone else either), as the big EEK project continues. Luckily I have been given an extended deadline, which was very welcome. I'm still in the recording stage, so I can't tell you if there's anything very interesting there, as these things usually first show up when you start number crunching.

But I've seen some interesting stuff online:

- Medieval horse harness with lots of bling found in Ireland. I'd love to see it in person, or, better yet, a reconstruction so you can see how shiny it would have been when it was in use.

- Excavations in northern Germany seem to have found the remains of Sliasthorp, a town connected to the Norse elite of the area. Sliasthorp lies near the trading centre Haithabu/Hedeby, similar to the situation of Adelsö and Birka in Sweden (possibly Uppåkra and Lund as well, although Lund was founded much later). This suggests that the founding of these trading places may have been directly associated with the elite rather than with traders. The trading places would also have been under control of the elite.

- And if you're interested in Flemish archaeology, Onroerend Erfgoed (the Flemish equivalent of English Heritage) has put up several of their publications online, which you can both search and browse. There is no English version of the site, but it seems fairly straightforward.

- The knitted 16th century cap collection of the Museum of London is now online. 73 caps, coifs, cap fragments, linings and earpieces have been photographed, with captions containing contextual and technical information. To browse the caps, please go to the Collections Online and enter ‘cap’ in the Keyword field with the date range 1500-1600 in the search fields.

- The seventh conference on experimental archaeology will take place in january 2013 at the University of Cardiff, Wales. Papers on any any topic related to experimental archaeology are welcome, but those that touch on the relationship between experimental and experiential* approaches are particularly welcome.The deadline for papers is July, although the webpage doesn't state if it's the first of the month or the end of the month. Hopefully the latter.

*: An experiment can be repeated by the same researcher or others. Experiential archaeology is about the experience, for example building an Iron Age house and live in it to see how the construction worked in practice. What most of the re-enactment community call experimental archaeology is in fact experiential.

- And a very interesting post from Bones don't lie discusses new research on using stable isotopes for sexing human remains. While there is an overlap in the ratios of iron isotopes between males and females, the overlap was not greater than a normal sex determination using the pelvis. Only one French assemblage was used for the study, and obviously more research is needed to see what the results are for other regions.
ossamenta: Weasel skull (Default)
Written as part of the Frequently-Or-Not-So-Frequently-Asked-Questions project (itself part of the annual Three Weeks for DreamWidth), for the prompt "I've often wondered how archaeologists determine the sex of a skeleton - I know there are differences in the pelvis, but what else is taken to be a clue? I'm also curious about how accurate it is, and whether anyone's done any studies on that."

Sex estimation of skeletons is one of the fundamental methods of bone analysis, and, yes, lots of studies have been done on that. Essentially, there are three ways of sexing (human) skeletons: shape and relative size of the bones, grave goods associated with a particular sex/gender, and DNA testing. This post is primarily dealing with skeletal sexual characteristics, but the other methods will get a brief mention.

cut for length )
And finally, just remember that it’s always more complicated once you go into the details…


*: cis = having a gender identity that matches the sex one was assigned at birth. Opposite to trans gender.

Cross-posted to [community profile] archaeology and [community profile] fonsfaq
ossamenta: Picture of an owl from a Medieval manuscript (Medieval owl)
Sometimes sexing birds can be very easy:
Male and female mallard - From Wikimedia Commons

Sometimes it is difficult:
Duck skeleton

While there can be size differences between males and females of the same species, there is often an overlap, which makes it difficult to carry out a reasonably secure sex estimation. If you have a large sample, you can hopefully get two (somewhat overlapping) bell curves, but bird bones are rarely found in such quantities*.

From a European point of view**, normally there are two ways of sexing birds: presence of spurs (only on galliforms, i.e. chicken, pheasant etc) and presence of medullary bone. Medullary bone is formed in the bone shaft cavity on female birds when they’re laying eggs. This acts as a calcium buffer for the egg shell development. The level of medullary bone can vary, from a millimetre lining on the cavity to a fully filled bone shaft, probably depending on where the hen was in the egg laying cycle, and/or how calcium rich the feed is. Medullary bone are most often found in the femur and tibiotarsus (the thigh bone and the drumstick bone). Medullary bone sexing has two major drawbacks: It can only be observed in fragmented bones. Since bird bones normally are rather small, there is little need to portioning them by cutting them in two, as is done with bones from cattle, sheep and pig. It is therefore likely that we miss several egg laying hens in bone assemblages. Secondly, the method only counts egg laying hens, possibly not the preferred animals to slaughter.

Medullary bone inside a fowl femur
Medullary bone inside a fowl femur

Close-up of medullary bone inside a fowl femur
Close-up of medullary bone

Spurs are more straightforward when it comes to sex estimation, even if they only appear in a few species. However, just as with horse canine teeth, occasionally females have them too. The bone part of the spur forms separately and fuses with the bone shaft at six months of age, although this is very variable.

Male and female fowl tarsometatarsus
Male and female fowl tarsometatarsus


Sometimes spurs have been cut off, either as a way to castrate the fowl (or, possibly to prevent fights within the flock) or to make it easier to tie metal spurs on for cock fighting. Not that that was necessary, cock fighting did and does happen with "natural" spurs too. Sometimes a predominance of male fowl in an archaeological assemblage has been interpreted as occurrence of cock fighting, although, at least for the Roman period, cocks would also have been the preferred sex for sacrifice.

Medieval cock fighting, from MS Bodleian 264, fol. 50r.
Medieval cock fighting, from MS Bodleian 264, fol. 50r.

Conclusion: bird sexing is much easier with live ones!

(read more? Dale Serjeantson, 2009, Birds, Cambridge University Press.)


*: Not only are there normally less chicken on the menu than cattle, sheep and pig, but the thin bird bones are easily destroyed in the soil.
**: I don’t have the experience to say whether non-galliform birds on other continents have sexually distinct skeletal elements or not. If some of my readers know, please tell me!

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