Document Type


Date of Degree Completion

Spring 2017

Degree Name

Master of Science (MS)


Primate Behavior

Committee Chair

Lori K. Sheeran

Second Committee Member

Jessica A. Mayhew

Third Committee Member

Lixing Sun


The mammalian mother-offspring relationship, the first bond an offspring will form, is complex in its development, as well as its costs and benefits to both mother and offspring. Across various non-human primate species, researchers have extensively examined this relationship, yet very little is known about how it changes as offspring age. Mother-infant relationships within the genus Macaca, for example, have been observed for decades in both field and laboratory settings. Researchers have found species differences in maternal behavior, as well as a female offspring bias in female philopatric societies. However, little is known about the mother-offspring relationship of Tibetan macaques (Macaca thibetana) from the two habituated sites in China, Mt. Emei and Mt. Huangshan. In 1991, researchers at Mt. Emei focused on maternal behaviors and found a female-infant bias across the group. It is imperative to study both individuals, however, as mother and offspring contribute efforts into a feedback loop that cannot be defined from the mother’s perspective alone. During the summer of 2016, I observed 12 mothers and 19 immatures (juveniles: 1 – 5 years old; infants: < 1-year-old) at Mt. Huangshan, specifically their behaviors and spatial relationships. I used principal component analysis (PCA) to compress the number of behaviors. I calculated model optimization by backward selection was to predict the principal components based on the characteristics of the mother (i.e., age, parity, matriline size, and dominance rank) and offspring (i.e., age and sex). From these results, I concluded from mother and offspring perspectives that maternal investment biased female offspring.