Thursday, February 25, 2016

Owl Pellet Lab

We completed a dissection of an owl pellet, identified each bone, reconstructed the skeleton to the best of our capability, and defined what the animal was based on the varying bone shape and size. Once we reconstructed the skeleton, as much as we could, we found that it was once a smaller bird. The evidence that supported this claim was that the animal had a rather large breast bone-which mirrored that of the basic bird skeleton-, and had an elongated femur and leg bones- which eliminated the possibility of it being a smaller rodent.

In comparison to a human skeleton, the bird bones vary in many different ways- both in shape and size. One of the differences is the breast bone. On the bird, the breast bone is more rounded, protrudes from the ribs and spine, and is much longer- as it starts at the cervical spine and ends near the femur. The breast bone on the human, however, is flat and smaller than that of the bird. A second difference would be the size and angle of the talus, as it lies vertical and is much longer than the humans talus- which is small and semi-round. The third difference between the bird and human skeleton is that the curvature of the birds cervical vertebrae is much more drastic than that of the human.
Despite some differences, the human and bird skeleton do have similarities. As the picture above shows, the bird looks as though it is a tiny human skeleton, but once muscle and joints are added into the birds skeleton, the orientation and movement of the bones change. Continuing, the birds pelvis- similar to a humans- is curved and lies at the beginning of the femur. Lastly, many of the bones in the bird-the femur, mandible, and spine- all mirror that of the humans, even though the orientation of the bones change.

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