Mystery bones

 Yesterday, my mum found a bone round the back of the place where she works, and knowing that I'd be interested in it, brought it home. Today, I've been having a good look at this bone, and trying to identify it.
First of all, this is a pelvic bone, or rather, it is half of the lower section of the pelvis. Here's a different version of the first image, with labels.

The hole is called the obturator foramen, and the place labelled acetabulum is the socket where the leg would attach.
It is great to be able to study an animal pelvis, but what I am most interested in is what sort of creature this bone came from. I would love to know the sex of this animal, how old it was, what sort of life it led, and how it died - but those would be more difficult to find out. Therefore I must satisfy myself with finding out the species which owned this pelvis.

My first thought was fox, so I did some research and looked at some images on the Internet. As far as I could tell from the pictures I saw, the pelvis was about the right shape, but the size was all wrong. I looked at some images of a fox pelvis being held up against a tape measure, and of people holding the bone in their hands. I worked out that the average length of this part of the fox pelvis is around 4 centimetres long. However, my bone was 9 centimetres long! So, although I may be wrong, I have for now ruled out fox.

If a fox pelvis was too small, then the same must be said for many other British mammals, so my thoughts turned to deer. I thought that perhaps the pelvis could have belonged to a baby deer. However, from my research it looks like a deer pelvis would be the wrong shape. There would be a more pronounced ridge (which I am having trouble finding the name for, I believe it may be called the ischiatic spine) leading away from the ischiatic tuberosity, if it was a deer. However, my pelvis does not have a very pronounced ridge, though I suppose it could be because it was from a young deer which had not developed properly yet. I'm not sure, but I think that I can cross deer of of the list.

So, that's fox and deer ruled out, I think. What does that leave? I am certain that this pelvis belongs to a mammal, but what mammal other than those already mentioned have a pelvis like this? I am thinking perhaps a dog, but I am uncertain. Really, I am not sure enough to say that it definitely isn't a fox or a deer - who knows, I might be surprised.
For now, this mystery is unsolved. I asked around on Twitter earlier on today, but I haven't yet had any replies. I will post a new update soon, to continue the story of the mystery pelvis.


However, the pelvis isn't the only unusual bone I'm going to be talking (well, writing) about today. While researching about the mystery pelvis, I decided to try and identify another bone that I have found.

My mum and I found this last year while rockpooling in Filey. In fact, we actually found this bone in a rockpool. We puzzled over it for a little while, and at one point we thought that it might be a seahorse bone. However, we soon disregarded this, and after that this bone was left forgotten in my curiosity cabinet for another year.
Today, I finally remembered it, and decided to try and identify it. This 6 centimetre long bone was not so easy to place as the previous one I talked about. Before, it was obvious that it was a pelvis, but this time, what kind of bone it was alluded us. However, I quickly discovered what it was after a few minutes of searching. Strangely enough, it is actually a part of the hip! However, this was not immediately clear because this small part does not include the the acetabulums (where the leg bone would fit in).
This bone, it turns out, belongs to a bird, probably some kind of seabird given that we found it in a rockpool. Birds have a very strange, elongated pelvis, topped with a part known as the synsacrum - which was what we had found.

 By Renegade Lisp - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=11174395

Above you can see a synsacrum of an unidentified bird. Now compare it to my bone:

 As you can see, my specimen is only a part of the synsacrum - normally it would have other bits on the sides, as you can see from the other image.

The synsacrum is used to make the pelvis more rigid, allowing it to withstand the rigours of flight. The holes that you can see in the picture above are presumably to make the bone lighter, a necessity for a flying animal.

So there you have it, 2 mystery bones, one identified, one still unknown. Keep an eye out for further updates on the mystery pelvis.

Until next time, keep on the wild side!