Giraffe Skull, Giraffa camelopardalis
Dr Phil Cox, former PhD student at the Museum of Zoology, writes:
No visitor to the Museum can fail to notice the mounted giraffe skeleton on display in the lower gallery, towering over the other mammal skeletons. It is great to be able to stand next to the giraffe to get a feel for just how tall these creatures actually are. However, because of its height, it is difficult to get a good look at the giraffe’s skull. Therefore, the specimen I have chosen is not the mounted skeleton, but the adult male giraffe skull in the nearby cabinet that is conveniently displayed at (human) eye-level. From this perspective it is much easier to see just how large and impressive the giraffe skull is. I can also confirm that it is extremely heavy. As part of my PhD, which was an investigation into the bone structure in and around the eye-socket in mammals, I wanted to examine and measure the giraffe skull. It required two people (Ray Symonds, the collections manager at the time, and myself) to lift it off the shelf and on to a nearby table. It is the weight of the skull and the length of the neck that enable male giraffes (bulls) to use their heads as club-like weapons during duels known as ‘necking’. Such contests occur between male giraffes in order to establish dominance, and involve the bulls swinging their necks and trying to hit each other with their ossicones (the horn-like structures on the top of the head). Having experienced the weight of this specimen first-hand, I was not surprised to find out that a well-placed blow from the head can knock a fully-grown bull completely off-balance.
Eo D61 Morganucodon (=Eozostrodon) watsoni
From Pontalun quarry, near Bridgend, Glamorgan.
Photograph of specimen Eo D61 Morganucodon (=Eozostrodon) watsoni
© Dr Pam Gill
Reconstruction of the lower jaw of Morganucodon.
© Pam Gill
Dr Pam Gill of the School of Earth Sciences, University of Bristol, writes:
This specimen is part of the lower jaw of one of our very first mammal ancestors. It lived in the Early Jurassic, 200 million years ago, at the same time as some of the earliest dinosaurs. Morganucodon (=Eozostrodon) was a tiny shrew sized mammal and it lived on a small limestone island in what is now Glamorgan, along with another early mammal Kuehneotherium. Hundreds of bones of these creatures accumulated in small subsurface caves, and have now been exposed by quarrying.
I have chosen this specimen of Morganucodon as it is one that was used to make a complete reconstruction of the lower jaw. Because the bones were broken when they were swept into the caves and there are no complete jaws preserved. This fossil is only a few millimeters long and is of the back end of the jaw, showing the strong jaw joint and the final molar tooth.
Eo D61 and other specimens were taken to the synchrotron in Zurich for high resolution CT scanning to make 3D reconstructions. Three specimens were digitally “stitched together” (see the image above) to make a complete jaw, with Eo D61 as the posterior end. Biomechanical models were made from the reconstructions of Morganucodon and Kuehneotherium and showed that Morganucodon could eat hard food such as beetles, but Kuehneotherium could only slice up soft food like moths. So even the very first mammals had evolved to eat different diets so that they were not competing for food.