On Friday I gave you a genuine mystery object from the Horniman’s collections:

It had been highlighted as potentially being human in origin, but it’s very short, despite being fully fused (therefore from an adult) and the condyles (the bumps that make the top of the knee) are too similar in size – humans have a bigger condyle on the inside of the knee.

However, the general shape is quite similar to a human femur – the depth and orientation of the condyles and the groove between them is all wrong for a quadrupedal animal and the femoral head and neck (the articulation at the top that goes into the hip) are at an angle and shape similar to that seem in humans.

There were some great observations and suggestions and I was pleased that henstridgesj managed to get the same identification as I finally decided on, with Matt King making a very similar suggestion. I think it’s the femur of a Common Chimpanzee Pan troglodytes (Blumenbach, 1775), since it looks like it belongs to a Great Ape, but it’s not robust enough for a Gorilla or Orangutan and it’s a bit too short and robust for a Bonobo.

I won’t go into too much detail about Chimpanzees right now – they probably deserve a bit more attention than I can provide at the moment as I have an article to write for submission tomorrow and a lecture to prepare for Thursday. I will try to come back to this fascinating species at a later time.

I will mention that although they are capable of bipedalism they tend to use knuckle-walking for most of their locomotion on the ground. In the trees it’s a slightly different story, where the arms can grip a trunk and the legs are used to walk up the tree with the feet providing additional grip. Very versatile and somewhat different to other monkeys (and yes – I said monkey, Chimps are apes, but they are also monkeys, as I’ve explained before).