Date of Award

2-1-2019

Document Type

Thesis

Degree Name

Master of Arts (MA)

Departments/Programs

Psychology

First Advisor

Diana Reiss

Second Advisor

Martin Chodorow

Academic Program Adviser

Karolina Czech

Abstract

Bottlenose dolphins (Tursiops truncatus) are socially sophisticated mammals with high fission-fusion dynamics and complex communication. The relative positioning of individual dolphins as they swim within their social group may aid in the expression of social roles. This study sought to quantify relative positioning in a small social group of female bottlenose dolphins at the National Aquarium in Baltimore that included two mother-daughter pairs, maternal and paternal half-sisters, a half-aunt and niece, and one unrelated female. We devised a method for scoring relative positioning in three dimensions. We found that the two mothers and their juvenile and adult daughters often swam in pairs, indicating that the mother-offspring relationship continued to be an important affiliation later in life. The two dolphins without a mother or daughter in the group, as well as the youngest juvenile female (one of the daughters), spent more time swimming alone than with others. Both of the mother-daughter pairs frequently swam in a position known as the infant position in the literature, despite the fact that both of the daughters in our group were 8 and 13 years of age. Among frequently associating non-mother/daughter pairs, there was some evidence that one dolphin typically stayed in front of the other, possibly indicating leader/follower roles. Conversely, there was no evidence that any dolphin stayed to the left or right of another; to the inside or outside of another in relation to the pool wall; or above or below another. A discussion of the application of developing technologies, such as machine learning techniques and unmanned aerial vehicles, to future research on relative positioning in cetacean social groups is included.

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