Document Type


Date of Degree Completion

Spring 2017

Degree Name

Master of Science (MS)


Primate Behavior

Committee Chair

Lori K. Sheeran

Second Committee Member

Kathleen Barlow

Third Committee Member

Gabriella Skollar


Few studies have explored the continuing relationship and behaviors within primate groups as the offspring mature and continue to depend on parental care. Between June 7 and July 7, 2016, I studied the family dynamics of 5 gibbon groups from 4 species: hoolock (Hoolock leuconedys), Javan (Hylobates moloch), pileated (H. pileatus) and northern white-cheeked (Nomascus leucogenys) gibbons housed at the Gibbon Conservation Center (GCC) in Santa Clarita, CA. I recorded all occurrences of approach, retreat, groom and play behaviors as well as the proximity individuals maintain between each other. I predicted: 1. offspring would be responsible for maintaining proximity to everyone in their enclosure older than they; 2. adults would not be responsible for maintaining proximity with anyone; 3. older individuals would spend more time in greater proximity to all other individuals in their enclosure; 4. older individuals would spend time grooming all other individuals in their enclosure; 5. younger individuals would only groom individuals older than they; 6. younger individuals would spend time playing with all individuals in their enclosure; and 7. older individuals would only play with individuals younger than they. While age was a factor in some behaviors, birth order, species and group make up also influenced individual behaviors. The results of this study will inform further studies in captivity and in the wild concerning gibbon group dynamics.