Document Type
Thesis
Date of Degree Completion
Spring 2026
Degree Name
Master of Science (MS)
Department
Primate Behavior
Committee Chair
Dr. April Binder
Second Committee Member
Dr. Eva Wikberg
Third Committee Member
Dr. Lori Sheeran
Abstract
The dear enemy and nasty neighbor effects are two different resource defense mechanisms defined by whether aggression is targeted towards strangers (i.e., dear enemy) or neighbors (i.e., nasty neighbor). Behaviors during intergroup encounters may provide insight into how an individual prioritizes resource defense and how individuals utilize indirect fitness tradeoffs. We studied expressed aggressive and stress-indicative behavioral differences between the presence and absence of intergroup encounters in adult male white-thighed black-and-white colobus monkeys (Colobus vellerosus) at Boabeng-Fiema Monkey Sanctuary in central Ghana. We used 5 to 10 minute long continuous focal sampling of males (N = 10) in four groups to record their interactions with each other and males outside the focal groups (N = 46 intergroup male focal samples, N = 202 non-intergroup male focal samples). We also used ad libitum sampling to record the start, end, and occurrence of intergroup encounters. We conducted an unpaired two-tailed t-test with Welch’s correction (95% CI) on five behaviors’ relative frequencies and relative durations. Results illustrate that vigilance and displace relative frequencies and durations are significantly higher during intergroup encounters. We conducted a Kruskal-Wallis ANOVA test with Dunn’s multiple comparisons to understand how kinship may iv influence adult male behaviors. Results showed that vigilance and displace behaviors both increased in frequency and duration in the presence of unrelated intergroups. Using observed home-ranges during the 2025 data collection period, 31 intergroup interactions involved unrelated neighbors while only five intergroup interactions involved unrelated strangers. Although stress-indicative behaviors were not observed to differ between neighbor and stranger intergroup interactions during this study period, C. vellerosus may still exhibit both a nasty neighbor and dear enemy effect based on adult males showing higher stress-indicative behaviors during intergroup presence than intergroup absence. Because most intergroup interactions are with neighbors, home-range and mate defense against neighbors may be particularly important for maintaining access to limited resources.
Recommended Citation
Tellez, Kayla, "THE DEAR ENEMY AND NASTY NEIGHBOR EFFECTS ON WHITE-THIGHED BLACKAND-WHITE COLOBUS MONKEYS (COLOBUS VELLEROSUS) AT BOABENG AND FIEMA MONKEY SANCTUARY" (2026). All Master's Theses. 2363.
https://digitalcommons.cwu.edu/etd/2363