Saturday, 26 November 2016

Adventures in medium sized mammal bone preparation

I think the zooarchaeology short course at Sheffield really inspired me, as now I think about animal bones as well as soils and plants in all situations. I'm currently working in central Oregon doing some preliminary work for the NERC project. As I continue to work in this region, we will need to build reference collections to work with. This is built into the NERC project, in terms of a plant microfossil reference collection. Animal skeletons in general are not so easy to get a hold of as plant specimens. Being the resourceful, perhaps slightly strange academic that I am, I noticed a few carcasses by the side of the road and figured why let them go to waste? The landscapes of the USA are so different to the UK, and something that is very noticeable is the amount of roadkill. In the UK I think animals that are hit by cars are cleared up pretty quickly. In the US the roads are much bigger, and animals that are hit just stay there. Or get removed by scavengers. This week I noticed what looked like a racoon at the side of a road. My very patient husband kindly pulled up the truck for me to check it out, and it turned out to be not just one, but two poor racoons. A male and female pair, both must have been hit running over the road, but there was no obvious sign of physical trauma or damage to the carcasses. So, we put them in the back of the truck (the male was noticeably heavier than the female). On the same day we also came across a hawk. He had obviously been there a bit longer than the racoons as there was some degradation of the eyes, and signs of scavenging on the torso. But the skeleton didn't look damaged. I am not 100% sure what species he is, but most likely a Cooper's hawk. Into the truck!

I did a lot of reading about the best way to prepare specimens for bone reference collections when I prepared some fish a while ago. I used a cold water maceration method for the fish, but given that this would involve skinning and gutting two medium sized mammals + plucking a bird of prey, the method is not at all appealing. I thought I'd try the open air decay method instead. As I will be away for about 6 months before I come back to do more fieldwork, this seems the ideal method, to let the organic matter decay naturally. This landscape is perfect for it. We find loads of small mammal bones wandering around the sagebrush, all perfectly defleshed and bright white. We set up an old dog crate and put them inside, to protect them from scavenging. I'm thinking about whether to ask my sister in law to visit it occasionally to take pictures of the decay process. I'm really curious to see how long it takes until only the skeletons are left, and the difference between the hawk and the racoons.