Strange bones #12: the mystery metacarpal

This bone might not like a mystery at all if you know a bit about bones. But there are two big mysteries:  what animal is it from, and how did it get there ?

Dad found it two weeks ago when walking in Suicides Graves wood. It was in the south-west corner, maybe quarter a mile away from where I found the red deer calf bones, and it was well inside the wood itself, away from the fields. It is easy to see it is either a metatarsal or metacarpal (which is a lower leg bone) from an animal like a sheep or deer but that doesn't solve the mystery.

Here's a boring bit that you can skip if you know about hand or foot bones: in humans metatarsals and metacarpals are in the hands (metacarpals) and feet (metatarsals). They go between the wrist or ankle and the knuckles (or first toe joint). In humans there is one bone for each finger or toe, and it is the same in some other mammals like seals, cats, dogs and foxes and so on. This is what my squirrel skeleton paw looks like. The four long bones in the middle are the metacarpals. The small ones to the right of that are the wrist bones. The four smaller bones are the phlanges (finger bones, some are missing):

But in some other animals, especially grass-eaters like cows, deer and sheep, there are two which are joined together in one bone. This picture shows the difference between my hand and a deer foot. The blue lines are the metacarpals (I have only drawn in two fingers), and the green and yellow lines are the phlanges which are finger or toe bones. The green are the proximal phlanges, the yellow are the intermediate phlanges and the final one which I haven't drawn in are the distal phlanges.

But you don't need to worry about the names because my point is that in deer the bones are joined together and the deer metatarsal or metacarpals are much longer. For example here is one of the young red deer hinds at Titus Well running along:

...and you might think the foot bones are all in the hoof, but they aren't. The last long straight bone in the legs is the metacarpal (front) or metatarsal (back) so the wrist or ankle joint is about half way up the leg.

Here are the front legs close up with the blue being the metacarpal, the green being the proximal phlange, the yellow being the intermediate phlange, and the final one that isn't marked is the distal phlange. So deer 'feet' might seem tiny, but they are huge if you think about it because the metatarsal and metacarpals are so long and big.

On deer, the metatarsals at the back are much bigger than the metatarsal at the front. These two are from the same adult red deer.

The way to tell whether a bone is a metatarsal or a metacarpal is to look at the end at the ankle or wrist joint. Metacarpals look like a "D". Metatarsals look like an "O".

This sounds like a boring biology lesson but it helps with the mystery bone because it's definitely a front metacarpal:

The other end of the mystery bone is interesting too because it shows the animal was young and still growing:

because if it was adult, the ends would be fused on like this red deer:

So it was a metacarpal from a young animal. But the puzzle is this: the bone is quite thick and big for the normal animals bones that I find. It might not seem that big:

but this is it compared to other metacarpals I have in my collection:

The shape is most like the newborn animals, because of the long cracks where the two haven't fused properly yet. And although it's not as long as a red deer, it is much much thicker. Long metatarsals and metacarpals usually mean the animal is designed to run fast. Thick metatarsals mean it is a heavy animal.

So it is a young big, heavy, slower grass-eating animal, heavier than a red deer and much bigger than a sheep. That really just leaves cow or horse. But there aren't many horses nearby, but there are cows around the edge of the field. So my best guess is cow. But how did a cow bone get in the middle of a dense wood ? My best guess is that a fox dragged away a part of the body to eat.

Have I got it right or do you think I have got it wrong ?

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