HEARING — FIELDWORK AND EXPERIMENTS 79 



Let the tank in which you keep your Hzards have a good 

 carpet of dried leaves at one end. Once you have got your 

 Hzards tame (which only takes a few days), introduce some 

 mealworms into the place where the leaves are; they will 

 soon vanish from sight among the leaves. The lizards, if 

 hungry, will be seen to look alert and this means that they 

 have heard the movements of the mealworms. They will 

 approach the leaves giving every sign of listening by turning 

 their heads sideways and downwards. They will then move 

 the leaves with their snouts (sometimes with their front feet) 

 and, with their tongues going in and out to pick up scent 

 and their sharp eyes looking here and there, they will seize 

 and eat the mealworms they uncover. This is an interesting 

 demonstration of what might almost be called "team work" 

 of the senses, because the prey, being at first hidden, is 

 detected by hearing; then both scent and sight are used in 

 the final capture. 



The very acute hearing in lizards may also be observed in 

 their habitat, though this demands some patience and good 

 luck. Two persons are required and the procedure is as 

 follows. 



You must first know of a place where either our Common 

 (Viviparous) Lizard or its larger relative the Sand Lizard 

 is known to be present. If the site in question is familiar to 

 you, there will probably be special spots where lizards have 

 previously been seen sunning themselves, and you will, I 

 hope, have noted these carefully. Lizards are very conserva- 

 tive indeed regarding these basking spots, and if no predator 

 has taken the lizards in the interim, there is every reason 

 why you should be reasonably certain of finding them there 

 day after day, if the weather be warm and sunny. It should 

 not be too hot, for both snakes and lizards dislike undue 

 heat. The best times of day are between 9 a.m. and 1 1 a.m., 

 and 5 p.m. to 7 p.m. These periods are, of course, variable 

 to some extent, depending on the temperature and precise 

 situation; but the point to be remembered is that the real 

 heat of a spring or summer's day will not be conducive to 

 finding lizards lying out. 



Let us suppose that you have your area planned and that 

 the conditions are favourable. You and your companion 



