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The six things I learned from Pharoah's post-mortem


Last week I wrote about how I rotted down the mummified body of Pharoah (I name my skeletons in alphabetical order) which was a canid that I brought back from Northern Ireland. It took me ages to rot down but when I did I discovered something interesting: it was not a dog which I had thought for two years, but a fox !

How did I know it was a fox and not a dog ? Foxes and dogs are both from the canid family, and they are the only two types of canids you find in the wild in the UK. In other places you can find other canids like wolves, coyotes and jackals. Here are the signs I looked for to tell a fox and dog apart:

This is the skull. It only had one half of the lower jaw because the other one had dropped out when it died. Dog skulls come in all different shapes and sizes but there is only one type of red fox skull, where the skull slopes gently from the top of the head down to the nose.

This next picture is Pharoah's skull at the bottom against Vulpy's skull at the top. Vulpy was a fox skeleton that I was given by a gamekeeper, and it is a skeleton from a female young adult skeleton. Pharoah's skull is 14.8cm long, which is slightly longer than Vulpy's, and it is wider at 9cm as well. The spikes of bone above the eye sockets are bigger on Pharoah as well, and the sagittal crest, which is the line down the middle of the braincase is bigger as well, meaning it had stronger jaws.

This shows that Pharoah on the right has a big sagittal crest but Vulpy barely has one:

This shows the snout of Pharoah on the left and Vulpy on the right. The bone plates have fused much more strongly on Pharoah than on Vulpy, which happens when you get older.

All these things so far make me think that Pharoah was older, stronger and bigger. This makes me think Pharoah was more likely to be a male because often in mammals the male is bigger. A good way to check is usually the pelvis. These are Pharoah's hips:

The two halves are fused together which happens in older animals. In deer the v-shaped notch on the right shows whether it is male or female with females having a bigger notch. I wrote about this with deer before. It's hard to tell with this but I think it's a male.

This is how the right femur ball goes in the right hip joint. It was all smooth and there were no signs of old age.

This was how I checked that it was definitely a fox: this is the upper canine with Vulpy's jaw in the background. A dog's canines would be thicker and blunter:

This is what the rest of Pharoah's upper jaw looked like:

At the top there is no hole for the left top canine, and some of the other holes were filled over. This is unusual.

At the front, there were no holes for upper incisor teeth at the front, which is very unusual. The small indentation on the right of the photo must have been where the tip of the lower canine tooth on that side. All these things are unusual, and it makes me think it was damaged on the snout at one point.

All these things would have made it very difficult and maybe painful to the fox to bite into prey.

A lot of the paw bones were lost at some stage, but I still got a claw bone:

There were some but not all of the tailbones. They were a different colour as if some of the fat had been absorbed into the bone:

These are the two humerus, which is the bone between the shoulder blade and the elbow. The one at the bottom, which is the right humerus, has an extra lump of bone on it but no other obvious damage. 

I hadn't seen this before my dad asked a vet friend who said the growth was at the point where a muscle attaches to the bone, and it had had some damage there (vets call it 'trauma'). I don't know what caused this.

This is the tibia (thick one) and fibula (thin one) which are the bones in the shin. Foxes have both these, like humans, but deer don't. In older animals these bones start to fuse together but they haven't here yet.

This is the end of the femur which is the bone between the hip and the knee. The left femur has an extra growth of bone at the knee end:

Dad checked with the vet again who said it was a sign of arthritis, which is a sign of old age when the joints start to stiffen up and hurt.

The last bit I want to show you is this scapula, which is the shoulder blade. This one is the left one, and instead of being smooth it is rough at the far end, and the bone is rippled and thicker than the other one:

This is the worst part, at the bit closest to the spine. It was obvious that it had had some damage here:

Dad had the idea of putting them both on a lightbox to see the thickness of the bone. Here the darker parts are thicker, and the damaged one is on the left:

From this I noticed two very light patches at the end closest to the spine so I looked back at the bone. If you looked close enough there were two small holes all the way through the bone !

I had a think what might have caused these, then I thought maybe they were bite marks ! Next week I will write about how I tested this and eventually found out what had bit Pharoah !

Anyway, these are the things I found out from looking at the bones:

  • It was an old male fox that had a violent life
  • It was strong
  • It had arthritis on the back left leg
  • It had a bite mark in the left shoulder blade
  • It had some damage where it lost the top left canine and all the upper incisors.
  • It had damage to the right humerus

Is there anything you think I have missed or got wrong ?

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Psydrache said...

Great detective work, jake! You have a wonderful fox skeleton in your collection now. I think the poor old fox was hit by a car once and so he lost the teeth and maybe got damage on it's scapula as well.

Emily said...

Amazing stuff, Jake!
I wonder if the lump on the right humerus could be where the tendon attaching the muscle has ossified (become bony). This sometimes happens in humans if you have very big muscles - you can see them on the bones. Perhaps the injury to the left scapula caused the fox to use it's right forelimb a lot more, so it's muscle got a lot bigger and left this ossified muscle attachment?
That's what I thought, but I'm not sure if I'm right! :)I'm a masters student doing bioarchaeology so I study the bones of animals and humans, and your site is REALLY useful! Thanks :)

Jake said...

@Psydrache - it's actually my second fox skeleton after Vulpy, which was a dead fox I rotted down.
@Emily - not sure but might be. Thanks !

ossamenta said...

Ooh, I like your pathological fox!

When I studied skeletal anatomy, I was taught that fox skulls could easily be distinguished from whippet-type dog skulls by putting a piece of lead shot (or similar small object) on top of the orbits - fox skulls have a small hollow that the shot can rest in, on dogs it will roll off immediately. For the post-cranial skeleton, it was more tricky, unless you had a good comparative reference collection. "Slender" is a good word to categorise fox bones, but it is such a non-absolute definition....

Jake said...

Hi ossamenta ! Brilliant tip !

Sea Wolf said...

Have seen older mammals with mouth damage like that. Tooth abscesses in the jaw eat away at the bone surrounding them. A bad infection will also spread along the jaw to other tooth sockets. A broken tooth will do this as well as other possible mouth injuries. As the infection travels along the bone and degrades it, the other teeth fall out as there is no support for them. It would have been interesting to see the mouth of that poor old fox and see if the damage had healed or if he was still suffering from an infected jaw. Not being able to hunt properly would have ended in the demise of this old warrior eventually.

Jake said...

Could be ! Thanks !

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