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Saguinus oedipus in a Habitat of Brotherly Love

By: Haley Atkinson | Mentor: Frank Logiudice


Twitters are the vocals heard most often. It is considered an indication that a more hostile interaction is imminent. Twitters often escalate into trills, and trills into physical movements, such as a chase or fight (Figure 4). If impact is made, then trills, loud sharp notes, and long rasps are the primary vocalizations heard. Broken rasps are heard infrequently only during extremely violent wrestling. Vocalizations rarely escalate above a long rasp, but broken rasps occur in a few instances (Figure 4). If an attack does not occur, vocalizations escalate to trills and, rarely, a loud, sharp note until appeasement or retreat is made.

Figure 4. Chart indicates total frequency of vocalizations made by main subjects during observation periods.

Twitters are often accompanied by both submission and dominant behaviors. After vocalizations are made, an attack usually starts with Ted lunging at Mini and making contact, usually by placing a hand on Mini (Figure 5), which leads to a chase or fight. The interaction ends when one or the other stops advancing and retreats.

In Pre-Enclosure B and Post-Enclosure B, Ted is not observed approaching Mini, only twittering towards him. The distance of Mini from Ted does not matter, only that Mini is within Ted's sight. Generally speaking, if Mini is seen, Ted first performs behaviors and movements that indicate a threat is nearby. Behaviors include silent freeze, head down/crouching, and crown smoothing. If Mini does not retreat in response to the behaviors and vocalizations performed, Mini physically approaches Ted, which causes Ted to perform aggressive and dominant behaviors along with intensifying his vocalizations. These behaviors and vocalizations include crown raising, readying his body into a lunge position, face-to-face vocalizing displays, and twitters that escalate into trills (Figure 4). A face-to-face vocalization is characterized by Ted grabbing Mini's head, placing his face to Mini's, and trilling or sometimes producing a loud, sharp note.

Figure 5. Chart indicates total number of times Ted and Mini are observed vocalizing and initiating aggression in both PreEnclosure B and Post-Enclosure B.

Pre-Enclosure B

When the family was confined to Enclosure A, a fight occurred at least once every time an observation was conducted (mean: 7.1 fights) (Figure 6). The greatest number of attacks observed is 19 times during one observation period. Hostile vocalizations are heard most often in association with fights and rarely in the absence of physical contact. It was soon evident that Ted is the source of the vocalizations and attacks (Figure 5). This pattern does not change once Post-Enclosure B opens.

Post-Enclosure B

Once Enclosure B is opened, there was a dramatic decrease in agonistic behavior (Figure 7). The amount of physical interactions decreased, but the total amount of interactions stayed the same with vocalization interactions increasing (mean Pre-Enclosure B: 7.08 fights; mean Post-Enclosure B: 0.40). Only one fight was observed in the first two weeks after Enclosure B was opened. By observation 15, the fights subside and aggressive interactions ended in a chase or aggressive vocalizations. Nevertheless, the duration of each chase or vocalization interaction increased before one individual retreated. The exact duration of the prolonged interactions was not recorded.

Figure 6. Chart indicates number of fights observed per observation for the first 13 observation periods before Enclosure B opens. A downward trend is seen due to construction starting at observation 5, which causes the troupe to become easily distracted or interrupted in their normal behaviors. For example, there is heavy construction being conducted during observation 10.

Towards the end of the study, the prolonged interactions became more hostile once the "newness" of Enclosure B wore off. By observation 21, fights started occurring again (Figure 7). Ted had since developed a displacement behavior observed only a few times where he would crouch and rub his nose back and forth on the substrate he is sitting on. This pattern was originally observed when he started to seclude himself from the others, which was first observed during observation 20.

In a few instances, Ted was seen "hiding" from Mini. He ducked behind a conspecific or moved to a place as to not be seen by Mini when Mini was nearby. While "hiding" behavior was being performed, Ted peeked from his hiding spot to see where Mini was. If Mini was too close, Ted started to twitter and crouch to prime for attack and retreat.

Figure 7. Chart indicates decrease in fights observed per observation period for the last 10 observation periods after Enclosure B opens.