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OWL PELLET LAB
Data Sheet and Questions

Name: ________________________________________

Species (and number of individuals) Identified in the Owl Pellet based on the key:

Questions: write answers on separate sheet(s) of paper

QUESTION 1: If you were to collect all the owl pellets dropped from an owl for a whole year, what information could be obtained from the owl pellets? Be complete (give at least four major things).

QUESTION 2: Given these data on percentage of barn owl diet that each prey type makes up in a year (for example, 30% of the diet of barn owls in the state of Washington are mice), please answer the following questions:

Prey type British Columbia Oklahoma Texas Washington
Voles
66
1
2
55
Mice
3
35
40
30
Rats
1
54
32
1
Shrews
13
4
15
5
Other
17
6
11
93

Ignoring the "Other" category, what pattern do you see that would allow you to predict barn owl diet in another state/province ? Give a possible reason (hypothesis) for the pattern (hint: how do the habitats compare among the states/provinces).

QUESTION 3: DENTAL FORMULA: When identifying mammals, we often use their dental formula (the number of each tooth type on one side of the skull for both the upper and lower jaws).
Example:
3 1 4 2 (Upper left jaw incisors, canines, premolars, molars)
3 1 4 3 (Lower left jaw incisors, canines, premolars, molars)

This mammal has 6 upper (3 upper left jaw and 3 upper right jaw) and 6 lower incisors, 2 upper and 2 lower canines, 8 upper and 8 lower premolars, and 4 upper and 6 lower molars on one side of the skull for a total of 42 teeth in its head.

Diet may by indicated by the dental formula as indicated in the examples below:

Dental Formula Type of Feeding Representative Groups
1/1, 0/0, 1/1, 3/3 Bark, nuts, roots Beaver, porcupine, many squirrels
2/1, 0/0, 3/2, 3/3 Browsing (twigs) Rabbits, hares
0/3, 0/1, 3/3, 3/3 Grazing (grass) Deer, bison, sheep
2/2, 1/1, 2/2, 3/3 Omnivory Humans
3/3, 1/1, 4/4, 2/3 Predation Dogs (incl. coyotes, fox), bears
3/3, 1/1, 3/2, 1/1 Strict Carnivores Cats (incl. mountain lion, bobcat)

State three generalizations you can make that would allow you to predict the general type of feeding that an animal uses if you found a skull and recorded its dental formula. Give a possible reason (hypothesis) for each generalization you make. Hint: you may want to look up the function(s) of the various types of teeth (incisors, canines, premolars, molars).

Jump to Lab Manual, Owl Pellet Lab, Key to Skulls