46 THE SENSES OF ANIMALS 



they have to shift position in order to get near enough to the 

 creature they are attracted to. 



Salamanders, being less aquatic than newts, are very suit- 

 able for observation in a vivarium, and will feed readily 

 under captive conditions. The Spotted Salamander is easy 

 to obtain and, when fully grown, may be eight inches or so 

 from snout to tip of tail. They prefer larger prey than newts 

 do, and worms are a good staple diet; but they will take 

 smaller prey of the same kinds as those taken by newts. Their 

 vision is good both by day and night and observations on 

 their ability to catch worms, insects and so on can easily be 

 carried out. 



Before moving on to the next group of animals it is worth 

 noting that though it may be thought that the use of sight 

 in the feeding habits of newts must be well known and under- 

 stood, surprisingly little work has been done on this. Further 

 experiments would be worth while in order to determine not 

 only the distances at which newts can perceive food items, 

 but also to find out how wide a range of insects and other 

 invertebrates newts will eat. It would be interesting to have 

 the results from a number of observers on whether newts are 

 put off by the scent of certain invertebrate creatures and if 

 so which ones ; it would also add to our knowledge of the 

 senses of newts to experiment with different species of worms 

 to gain some idea of newts' abilities to discriminate between 

 one species and another by means of smell and taste. These 

 senses will, of course, be referred to again when I come to 

 deal with them in future chapters. 



Reptiles 



The word "reptile", to the layman, often merely means "a 

 snake", and it is surprising to some that among the reptiles 

 are included, in addition to snakes and lizards — crocodiles, 

 alligators, tortoises, terrapins and turtles. 



In all these groups the eyes play quite an important part 

 in their lives, though I would hesitate to say that sight is 

 always the truly dominant sense. The differences in the 

 structure of the eyes of different kinds of reptiles belong, 

 quite properly, to Part II of this book; but to make the 



