NO, 5 BEHAVIOR OF THE NIGHT MONKEY — MOYNIHAN 33 



from three to at least twelve. The successive notes tended to rise 

 slightly in pitch. Sketches of sound spectrograms of three more or 

 less typical Low Trills are shown in figures 7, 8, and 9. 



2.400 



1.200- 

 960' 

 720 

 4^0 

 240- 



960" 



0.6 1.2 



Fig. 7. — A Low Trill, uttered by an adult. 

 Based upon a spectrogram by a Kay Electric Co. "Misstlyzer.' 



— 1 — — — T 



2.0 4.0 



Fig. 8. — One Moan, followed immediately by one Low Trill, uttered by an adult. 



Based upon a spectrogram by a "Missilyser" 



All Low Trills were uttered with the mouth closed or nearly closed. 

 They were not accompanied by any conspicuous inflation of the throat 

 region. 



They were uttered in several different situations. They were com- 



