Name: ______

A Study of Predator-Prey Relationships

Owl Pellets

Procedure:

1.  Examine your owl pellet. Describe the characteristic of your pellet in the space below. Use your “observations skills” to be precise.

2.  Weight your pellet before you begin your dissection. Record the weight.

Mass: grams Enter your mass into the class data spreadsheet.

3.  Carefully begin your dissection by removing the outside parts of the pellet first. Peel away the layers, and carefully remove any bones you find along the way.

4.  Separate your bones out into common parts. How many animals were found in your pellet? ______How can you tell? ______.

5.  Locate all your jawbones. Using your metric ruler record your jaw lengths in the table below. Round to the nearest millimeter. Only measure the first 8 you find.

1 / 2 / 3 / 4 / 5 / 6 / 7 / 8
mm / mm / mm / mm / mm / mm / mm / mm

Enter your jaw lengths into the class data spreadsheet.

6.  Save all bones of your prey in a plastic bag. Label the bag with your names and period. We will use these bones later in the school year.

7.  Complete the chart below when all data has been collected. Fill in the chart on the back, so you have all the class data to answer questions.

8.  Construct a graph with the entire classes jaw data (See step 2 on direction page). Attach to this paper.

9.  Conclusion- Answer ALL the questions (#3 – 15) in complete sentences on a piece of binder paper. Attach to this paper.

Table 1: Class data

a. Total # of Pellets / b. Total Mass of Pellets
(g) / c. Average Pellet Mass
(g) / d. Total Number of Jaws found / e. Average # of prey per pellet / f. Avg. Jaw length (mm)

Owl Pellet Masses (filled out Day 1)

Lab Number / Period __
1
2
3
4
5
6
7
8
Total
Average

Jaw lengths (Filled out Day 2 – all classes)

mm / Quantity / mm / Quantity / mm / Quantity
3 / 14 / 25
4 / 15 / 26
5 / 16 / 27
6 / 17 / 28
7 / 18 / 29
8 / 19 / 30
9 / 20 / 31
10 / 21 / 32
11 / 22 / 33
12 / 23 / 34
13 / 24 / 35