Animal Behaviour 



the immediate seizure of the moving object is satisfactory, since 

 almost all small insects and worms are part of a toad's or frog's 

 menu. But sometimes lack of examination of the object brings 

 dire results. Such is the case when a large stag beetle is 

 swallowed. Its huge pinching mandibles produce terrible effect 

 at once in the frog's stomach. Fortunately, the frog has a wide, 

 short oesophagus, so that any disagreeable object can be disgorged 

 immediately. 



This lack of examination of food has made possible various 

 stories about the toad: that is, that the American toad will seize 

 and swallow shot rolled toward him until he is heavy with it, 

 and that the Southern toad will again and again swallow the 

 burning ends of matches, mistaking them for fireflies. It also 

 explains an incident related in an old " American Naturalist." 

 A toad was seen to pick up an elm twig that had just fallen from 

 the tree above him, and the observer amusingly interprets that 

 the toad used the hands to play with the twig as though playing 

 upon a flute before finally dropping it. 



However, although frogs and toads do, as a rule, seize moving 

 objects without examination and will try to eat even one's finger 

 or pencil, nevertheless there are many exceptions. Especially 

 in the case of the toads is a more intelligent method often pur- 

 sued. The moving object, if it is at all large or formidable, may 

 be stalked some distance and examined closely. In fact, the toad 

 may discriminate the forward-moving end and makeispecial effort 

 to take the creature head first. If grass or earth are taken with 

 the food, the mouth distinguishes these through the sense of 

 touch, and the toad removes them, or tries to, using the hands 

 awkwardly for the purpose. 



Also after swallowing a stag beetle or a very large unman- 

 ageable earthworm, the toad learns by his experience, and 

 cannot be tem.pted again by the same or similar objects. The 

 permanency of the lesson has not been tested. Experiments with 

 labyrinth tests have proved that the green frog can profit by 

 experience.* The learning is very slow indeed, but after fifty to 

 one hundred experiences, a habit is perfected, and when tested 

 after the lapse of a month, still persists. 



The frog's sense of sight is fundamental not only in the cap- 



* The Instincts, Habits, and Reactions of the Frog. Robert M. Yerkes. Harvard Psycholo- 

 gical Studies, Vol. I. 



29 



