TARSIUS SPECTRUM 87 



of trees and underbrush. The manner in which it supports itself in this 

 vertical posture is interesting and peculiar. With the lingers and toes it 

 holds the branch in prehensile grasp, meantime pressing its long slender tail 

 against the branch very much in the manner of a spring. If the tail is pulled 

 away from its support, tarsier tends to sag downward. The tail, however, is 

 in no sense prehensile, nor is it used, with the exception above mentioned, in 

 other functions than as a balancing and steering organ during locomotion. 



Tarsius is humanoid in reproducing a single offspring at a time. It is not 

 gregarious, as many of the other primates are, but goes in pairs. After the 

 breeding season the female and her young usually live alone together. There 

 is no evidence that these animals build nests, or even live in the holes of trees. 

 \\ hen sleeping, the head sinks downward, much as that of an old man 

 asleep in his chair. Often the young tarsius will perch upon the mother's head 

 while she is thus sleeping, and in this position fall asleep itself. This is an 

 interesting motor combination, plainly showing that the mechanism for 

 maintaining the vertical clinging posture operates perfectly even though the 

 animal sleeps. 



The general behavior of tarsius seems extremely stereotyped. It is 

 capable of but little acquisition under training, and in captivity is apparently 

 unable to make new adaptations. In spite of its enormous eyes, it has diffi- 

 culty in securing its food during the daytime, grasping awkwardly at grass- 

 hoppers or other insects oflered to it. This no doubt is due to the fact that 

 its visual apparatus is specialized for nocturnal hunting, and also because 

 the retina possesses no macula. 



Characteristic in the motor activity of the tarsier are its marvel- 

 ous leaps from branch to branch, which are so swift as almost to defy 

 the human eye. It is said that the animal is able to capture small insects 

 on the wing in its leaps. On the ground it leaps also like a frog, but awkwardly. 

 When it lands it sprawls, and then hops away again. Only occasionally does 



