152 A GUIDE FOR THE STUDY OF ANIMALS 



4. Offer the squirrel various kinds of food and see if it 

 has a choice. Describe its methods of eating. 



5. Note the position of the eyes, the shape of their sur- 

 face, and the shape and size of the pupil. How many 

 eyelids do you notice.' Why do the squirrel's eyes ap- 

 pear so " bright " ? Are eyebrows, eyelashes, or tear 

 glands present ? 



6. Note the size, shape, and appearance of the squirrel's 

 external ears. 



7. What movements of the nostrils do you notice ? For 

 what does a squirrel chiefly use his nostrils ? What ex- 

 planation can you suggest for the nostrils, eyes, and ears 

 having the same relative position in all vertebrates .■• 



8. How does a squirrel protect itself ? 



9. Smear the feet of a squirrel with ink and allow it to run over a 

 roll of clean paper as in the case of the rabbit. How do its tracks dif- 

 fer from those of the rabbit ? 



Summary. 



1. What are.the general characteristics of the squirrel.' 



2. To what kind of life is it adapted ? 



3. What adaptations has the squirrel to protect it from 

 its enemies ? 



4. What characteristics make the squirrel a good pet ? 

 What objections to it ? 



Library Exercise on Rodents 



1. General characteristics and examples of rodents. 

 The teeth of rodents. 



2. Show how variation in habitat depends upon struc- 

 ture among rodents by comparing, for example, squirrels, 

 beavers, and woodchucks. ' 



3. Variations in the tails of rodents. What are the 

 causes of this variation ? 



