The Regurgitation Station

During today's lab, we dissected owl pellets. Owl pellets are collections of bones, fur, feathers, and other non-digestible things that owls swallow from their prey. Our jobs were to compare the structure of the small animals eaten by the owl to that of our human bone structure, while also trying to identify what animal was eaten.

In the pellet my partner and I had, we believe to have found a shrew, or at least some of the main parts of a shrew. The only skull we found was extremely small, only 1.2 cm in length, which is the median measurement of a shrew's skull. The mandible is also very distinct with its 2 large teeth and smaller teeth on the inside of the large ones.

In terms of similarity to human bones, there were quite a few bones that are shared between the two species. They include ribs, femur, and tibia/fibula. The ribs are exactly like ours, curved inward, but I did not find a sternum so shrews might not have one. The skull and mandible of the shrew is completely different from our skulls and mandibles. The shrew's skull if much more elongated and flat whereas our skulls are more vertically long. The nose holes for humans are a triangle with a thin separation between the two canals, For the shrew the separation between the two canals is significantly spread from each other. The mandible for us was split in two, shown on the left, and has a large incisor on each half of it. The other teeth on the inside of the large ones and are significantly smaller in comparison.