NO. 5 BEHAVIOR OF THE NIGHT MONKEY — MOYNIHAN 59 



patterns by adults is the sort of phenomenon which might be expected 

 to be produced by the abnormal circumstances of captivity. (If 

 nothing else, young animals raised in captivity tend to regard the 

 human beings that take care of them as their parents, and often 

 retain this attitude after reaching maturity, long after they would 

 have become independent of, or separated from, their parents in the 

 wild.) 



Other Squeaks uttered by adults may have a different significance. 

 Many of the captive adults on Barro Colorado Island uttered frequent 

 Squeaks during sexual reactions. This occurred often enough to 

 suggest that Squeaks may be a normal part of the adult repertory, a 

 normal accompaniment of sexual behavior even if not of any other 

 adult activity. 



Squeaks were uttered by both adult males and females. They 

 were uttered most frequently by individuals approaching their mates, 

 and just beginning to perform Allogrooming, but were relatively much 

 less frequent during the later stages (when Allogrooming was in full 

 swing and most vigorous). Squeaks also were relatively rare during 

 copulations and overt disputes between mates. 



As far as I could tell by ear, all the Squeaks uttered by adults were 

 similar to, or identical with, the "pure" Squeaks of juveniles in form. 



The function (s) of adult Squeaks in sexual situations were obscure. 

 They did not seem to produce any overt, positive, response in the in- 

 dividuals toward which they were directed. They may, conceivably, 

 have functioned as some sort of appeasement pattern. One might 

 expect that any behavior pattern that is performed most frequently 

 by infants and juveniles would tend to reduce hostility (especially 

 aggressiveness) in any adult toward which it is directed, even when 

 it is performed by another adult. 



EXAMPLES 



Some of the different sequences and combinations of Allogrooming, 

 copulatory, hostile, and other patterns during different types of en- 

 counters between males and females may be illustrated by extracts 

 from my notes made at the times of observation. 



The first is an example of the behavior of experienced males and 

 females. 



February 4, 1962. Z male and X female. These two animals are mates. They 

 were separated several days ago. The male has been kept in the cage in which 

 the pair lived previously. Tlie female has been kept in another cage (out of 

 sight and hearing of the male) by herself. 



7 : 40 p.m. Female put back in cage with male. Male is in sleeping box at the 



