NO. 5 BEHAVIOR OF THE NIGHT MONKEY — MOYNIHAN 37 



animals in captivity on Barro Colorado Island, if the mates were 

 well adjusted to one another, when one individual rejoined its mate 

 after being separated from it for a few seconds or minutes (the indi- 

 viduals that uttered Moans in such circumstances were long past the 

 stage of uttering Low Trills as "greetings"). Moans were not usually 

 directed by one individual toward its mate in other circumstances, 

 i.e., after they had been together for more than a few seconds. (The 

 only exceptions were a few Moans uttered during the first parts of 





—-— —— — " — ' — ■ — t -^ — ' » 



2.0 4.0 



Fig. 10. — One Moan, uttered by an adult. 

 Based upon a spectrogram by a "Missilyser." 



long precopulatory sequences. The animals that uttered these notes 

 did not utter more Moans immediately before or during the actual 

 copulations.) Some captive individuals on Barro Colorado Island 

 uttered Moans while they watched other individuals fight without 

 becoming involved in the fights themselves. A few individuals at both 

 Iquitos and Barro Colorado kept in cages with monkeys and marmo- 

 sets of other species but with no other individuals of their own species 

 uttered Moans regularly as they moved about their cages in an almost 

 perfectly relaxed manner. The other vocal patterns with which Moans 

 were associated most frequently were Low Trills, Gulps, and Sneeze- 

 grunts ; i.e., an individual that uttered Moans was quite likely to utter 

 one or more of these other sounds immediately before and/or after 

 the Moans. Both the Gulps and the Sneeze-grunts seem to contain 



