NO. 5 BEHAVIOR OF THE NIGHT MONKEY — MOYNIHAN 6l 



7:18. Male starts to approach female. She assumes an Arch Posture, starts 

 to advance toward him. He retreats . . . 



This sort of inconclusive behavior continues until 9:10, when I decide to stop 

 observations. Then, happening to pass the cage at 9:50, I find the animals 

 copulating I Resume observations. 



Copulation apparently successful. Male dismounts. Then mounts again imme- 

 diately. No preHminary display by either animal. Copulation again apparently 

 successful. Pelvic thrusts at intervals of at least several seconds. Then male 

 dismounts. No postcopulatory display. Male walks away a couple of feet. 



Back to female almost immediately. Approaches her from side. Sniffs at 

 her side and utters Squeaks. Climbs up onto her back, mounting from side. 

 Once mounted, he seems to be trying to shift around into a copulatory position. 

 Gets half way there, but female turns around to look at him, and he slides off. 

 Then walks away again . . . 



10:01. Male approaches female again. From side. Sniffs at her side and 

 utters Squeaks. Half mounts, from the side. Then he begins to groom the 

 female, while he remains sprawled sideways across her back. His grooming 

 movements are extremely vigorous, even violent, and very awkward looking. 

 Female just sits. Male eventually slides off. Remains sitting beside female, one 

 hand resting on her back, and utters many Squeaks at irregular intervals. Fe- 

 male eventually walks away. Male follows . . . 



10 : 10. Male grooms female steadily for several minutes. Reaching her from 

 side. He repeatedly turns her half way over on her back, apparently trying to 

 get at something under her arm on the far side. Both animals silent. Finally 

 the female breaks away. Male follows her. Uttering Squeaks. Then mounts 

 her from the rear. Tries to copulate. Copulation attempt probably unsuccessful. 

 Only one or two pelvic thrusts. Both animals silent. Then male slips off . . . 



10:19. Male approaches female again. Silently. Mounts her immediately, 

 from rear. Copulation. Apparently successful. Long sustained, with many pelvic 

 thrusts. Male finally dismounts. Sits beside female. She sniffs at his flank 

 region. He immediately starts to groom her. Grooming lasts only a few seconds. 

 Then male mounts again, from the rear. Copulation. Apparently successful. 

 Many pelvic thrusts ; the last one very long sustained and accompanied by quiver- 

 ing of the rear part of the body. Male slips off. Immediately starts to groom 

 female again. This AUogrooming is much more prolonged and violent than the 

 Allogrooming immediately before the last copulation. 



10:22. Male stops Allogrooming momentarily. Then starts again. Grooming 

 movements even more violent than before. Again and again he twists the female 

 over on her back. No attempt to mount. Female silent ; male utters occasional 

 Squeaks. Then the male stops Allogrooming and walks away. 



He goes back to the female almost immediately. Mounts her from the front, 

 climbing over her head. Lies on her back, his head over her tail, his tail hang- 

 ing in her face! He slips off after a few seconds, and the two animals sepa- 

 rate . . . 



This sort of behavior, including many copulation attempts (all apparently 

 unsuccessful) and much violent Allogrooming by the male, continues spas- 

 modically as long as I continue to watch the animals, imtil 11 :00 p.m. 



During this encounter, it was obvious that the male had a strong 

 copulatory tendency, but he seemed to have difficulty in orientating 



