222 THE PSYCHICAL KINSHIP 



it a sharp peck and utters a querulous kind of 

 cry, and the second one takes its turn. This is 

 prudence, or forethought, which is a form of 

 reason. When swans are diving there is generally 

 one that stays above the water and watches. 

 Sentinels have alarm sounds of various kinds, 

 which they give to signify ' enemy.' ' Ibex, 

 marmots, and mountain - sheep whistle ; prarie- 

 dogs bark ; elephants trumpet ; wild geese and 

 swans have a kind of bugle call ; rabbits and 

 sheep stamp on the ground ; crows caw ; and 

 wild ducks utter a low, warning quack.' 



In the Popular Science Monthly for March, 1901, 

 is an account of a series of experiments on the 

 intelligence of the turtle made by Professor Yerkes, 

 of Harvard. The turtle was placed in a labyrinth, 

 at the farther end of which was a comfortable bed 

 of sand. It took just thirty-five minutes of wander- 

 ing for the turtle to reach the nest the first time. 

 But in the second trial the nest was reached in 

 fifteen minutes, and by the tenth trip the turtle 

 was familiar enough with the route to go through 

 in three and one-half minutes, making but two 

 mistakes. The turtle was afterwards placed in a 

 more complex labyrinth, containing, among other 

 features, a blind alley and two inclines. The 

 inclines were puzzles, and it took one hour and 

 thirty-five minutes of aimless rambling for the 

 wanderer to reach its nest the first time. But 

 the fifth trip was made in sixteen minutes, and 

 the tenth in four minutes, which was not far from 

 direct. 



