Friday mystery object #262 answer


Last Friday I gave you this pretty characteristic mystery object from the Berlin Museum für Naturkunde to try your hand at identifying:

mystery262

There were lots of great comments – I must apologise for not responding to many (and for posting the answer to this mystery object so late), my excuse is that I’ve had an insanely busy week finishing up my old job at the Horniman Museum and Gardens and then getting started in my new job at the fantastic Grant Museum of Zoology at University College London (more to come about my big move). I also got started on a really interesting project looking at Gorilla osteology and I’m feverishly trying to prepare a training workshop on identifying natural materials for next week.

Back to the object. Several of you noticed the presence of a baculum (or penis bone) which shows us quite definitively that this was a male animal.

Panda penis bone (baculum) from the Berlin Museum für Naturkunde

It also suggests that the specimen was prepared and mounted without the prudishness that many historical mounts were affected by (see Jack Ashby’s comments about this in his post on the Grant Muesum’s Ringtail).

Many of you also correctly recognised that the plantigrade (or flat-footed) posture, short tail and robust build suggested a bear of some sort.

Panda hind limb bones showing plantigrade foot

The distinctive sagittal crest was the final feature needed for identification for some of you to work out that this is the skeleton of a Giant Panda Ailuropoda melanoleuca (David, 1869).

Panda skull side view

Panda_skull_top

I tend to think of Panda skulls as looking like a cross between those of a Hyaena and a Gorilla, which makes sense when you consider the adaptations of the jaw musculature required for the Panda to process the large volumes of tough bamboo needed to provide enough energy for survival. The bone of the skull has to be able to manage the large forces produced by all this chewing, resulting in a big and robust sagittal crest, a thick and deep mandible and really deep muscle scars on the coronoid process.

These are all features you also see in big chewers like the Gorilla and Hyaena, but not in rodents and ungulates – I think this reflects the difference between groups that rely on temporalis muscle (which runs along the side of the braincase) in chewing compared to the masseter muscle (which attaches to the zygomatic arch or cheekbone).

The final clue to confirm that this is a Giant Panda is the ‘thumb’ on the front limbs:

Panda_thumb_1

Panda_thumb_2

This handy (excuse the pun) extra ‘digit’ is actually the radial sesamoid bone of the Panda’s wrist, that has been commandeered by evolution for use as a bamboo holder. There are a few other species that have done weird things with wrist bones to gain a digit, but this is clearly not a Mole or Elephant and Red Pandas have a much longer tail.

I hope you enjoyed some of the interesting bony features of this specimen – it’s great to have a chance to see under the surface of such an iconic animal!

3 thoughts on “Friday mystery object #262 answer

  1. One issue with the baculum which I know that many biologists seem unaware of is that there’s an easy mnemonic to remembering which mammals possess one. The baculum is found in Primata, Rodentia, Insectivora, Chiroptera and Carnivora. 🙂

  2. I recently read that it seems Giant Pandas actually have two extra “thumbs”; one on each side. Any clues in you pics?

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