The strangest animal bone?

When I was up in the burials department in the office yesterday, I was asked what the strangest animal bone was? My thoughts first went to marine mammals, as their style of life, so to speak, makes for bone shapes very different from those of land-living mammals. But then it struck me: mole humerus! As opposed to (all? most?) other animal humeri, the mole humerus is almost as wide as it is long. It is clearly shaped the way it is since moles spends their lives digging through the soil, rather than walking on it as most other mammals. I can just about recognise the two joints on either end of the bone, but there are so many muscle attachments all over it that they are not immediately obvious.


Left: rat humerus (for comparison), Right: mole humerus. The rat humerus is unfused on top, which is why there is a visible gap between the two parts.


The rest of the bones in the front limb also differs, but in less obvious ways.


The mole scapula is so slender. The rat scapula on the other hand is very similar in shape to most other mammal scapulae.


The mole ulna is much more compact and with large muscle attachments on the top.


The difference between the hind limb (tibia/fibula and femur) of the rat (left) and mole (right) is less marked. The mole has again more compact bones with larger muscle attachments.

Readers: Any contenders for strangest animal bone?