NO. 5 BEHAVIOR OF THE NIGHT MONKEY — MOYNIHAN 7 



they are either aggressive or alarmed. In this respect, they are quite 

 different from many other New World monkeys, e.g., species of the 

 genera Aloiiatta, Ateles, and Cehiis, which tend to perform particularly 

 frequent and/or vigorous scratching in such circumstances. 



It is my impression that young Night Monkeys also may tend to 

 perform relatively more scratching movements with their feet, and 



TABULATION OF ORDINARY GROOMING AND CLEANING 

 REACTIONS 



Nximher'^ 

 Autogrooming performance of bouts 



Scratching the face with one hand 23 



— the side of the head with the hand of the same side 1 



— the chest with one hand 1 



— the side of the body with the hand of the same side 24 



— one hind leg with the hand of the same side 19 



— one foot with the hand of the same side 5 



— the genital region with one hand 4 



— the tail with one hand 4 



— one arm or hand with the other hand 16 



— the tail with both hands 3 



— the chin with one foot 2 



— the face with one foot 11 



— the side of the head with the foot of the same side 1 



— the chest with one foot 1 



— under one arm with the foot of the same side 1 



— one arm with foot of the same side 7 



— the side of the body with the foot of the same side 17 



Nibbling the fur of the tail 1 



Cleaning performance 



Licking a hand 3 



Rubbing the nose along the substrate 2 



1 This count is based upon observations of six individuals; two immatures and four adults. 

 The longest period of observation of a single individual was 1 hour. The shortest period was 

 12 minutes. 



relatively fewer scratching movements with their hands, than adults 

 in similar situations. There may be two reasons for this : ( 1 ) Young 

 individuals find it more difficult to balance with one hand off the 

 ground and (2) they can reach most parts of their (relatively shorter) 

 bodies with their feet more easily than can adults. 



Unlike most other platyrrhines, Night Monkeys seldom perform 

 allogrooming except in obviously sexual or partly sexual circum- 

 stances (see below). This presumably is correlated with their slight 

 degree of gregariousness, but it is not due simply to lack of opportu- 

 nity. Mated Night Monkeys rarely groom one another even when 



