Owl Pellet Dissection Lab

                   (An owl pellet)

Today we learned about and dissected owl pellets in class with partners. Owl pellets are made out of the parts of an owl's meal it cannot digest and use for energy mainly things such as fur, feathers, and bones since owls prey on smaller birds and rodents. First, my partner and I opened up the pellet and tried to pick out any bones that we could find from the fur that surrounded them. We picked out the skull which was falling apart due to the break down of the immovable fibrous joints that held it together. Then we tried to pick out the rest of the bones from the fur. Once we had taken out as many bones as we could find, we tried to put the classify and put the bones together to form a skeleton. From there, we measured out the length and width of the skull and the length of the lower jawbones in order to try and classify what type of animal we found within the pellet.

My partner and I believe that there were remains of a rat in our owl pellet. We came to this conclusion by first deducting that the creature inside our pellet was not a bird since there were no feathers and the skull and lower jawbones contained teeth, which birds do not have. Next we measured the length of the length of the lower jaw and the skull and found that the measurement was bigger than 25 mm and the lower jaw was exactly 20 mm. The normal measurements for a rat skull place the length of the skull at 25 mm or larger and measurements for the lower jaw in between 17 and 30 mm so our organism that we found within the pellet definitely fit into the category of a rat. We also know it couldn't be a mouse (the next closest thing to a rat) since a typical mouse has a lower jaw measurement of 9 to 16 mm which excluded our animal since it had a larger lower jaw.


  (bones and the skull of the rat)


  (bones and the skull of the rat)



                   (lower jaw)

Similarities I noticed between the rat and human skeletons:

1) Both rats and humans have more than one bone in the skull and these bones are fused together by immovable fibrous joints.

2) The teeth of the rat were positioned similarly to human teeth with molars in the back and canines in the front.

3) The rat skeleton contained many of the same long bones that a human skeleton contains such as the femur, tibia, fibula, clavicles (a flat bone), and a pelvis (an irregular bone).

Differences between the rat and human skeletons:

1) The rat skeleton had more bones in its vertebral column since it had a tail and that probably allowed the rat to arch its back more than a human can.

2) The rat has a longer skull than a human does.

3)  The rat's skeleton showed us that rats' generally have longer and more narrow hipbones unlike human hip bones which are shorter and wider.