Date of Award
5-12-2024
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Biology
Advisor(s)
Susan Parks
Keywords
animal behavior;behavioral ecology;bioacoustics;ontogeny;vocal learning;whale
Subject Categories
Biology | Life Sciences
Abstract
Studying variation in individual behavior can elucidate drivers related to factors like age, social context, and the environment. Differences in behavior with age are a product of survival needs and developmental differences as animals physiologically mature and modify their behaviors in response to experience. Learning is of particular interest across taxa because it is fundamental to the development of complex behaviors, from problem-solving to social hierarchies to animal songs and human language. Humpback whales (Megaptera noveaeangliae) exhibit a variety of complex and culturally transmitted behaviors across their range, including a diverse acoustic repertoire. Despite decades of research on adult behavior, we know very little about the behavior of juveniles and how mature behaviors develop. In this dissertation, I study individual humpback whale behavior and make age comparisons using data collected from sound and movement tags attached via suction cups. The data are from two populations and study sites: the Western North Atlantic feeding grounds in the Gulf of Maine and the North Pacific breeding grounds in Hawai’i. My first chapter addresses an important methodological issue and provides insight on the behavior of humpback whales in groups. Using simultaneous tags deployed on pairs and trios on the feeding ground, we use relative received levels of calls across tags to assign caller identity, allowing for descriptions of individual acoustic behavior including call rates, silent periods, and vocal exchanges that were not possible previously. The second chapter uses this simultaneous tagging method to characterize the acoustic behavior of humpback whale calves on the feeding ground and look at differences across age classes. We found that calves on the feeding ground are no longer acoustically cryptic and produce calls in bouts. Calves are also able to produce most of the adult repertoire but produce some immature versions of adult calls. The third chapter looks at the acoustic and movement behavior of yearling humpback whales upon their return to the breeding grounds. We found that yearlings occupy an intermediate stage of development between calves and adults. Yearlings dive deeper and longer than calves, suggesting increased aerobic capacity, and show differences in the acoustic parameters of a contact call compared to adults, which may reflect maturity of the vocal production organs. Finally, the fourth chapter describes humpback whale song session performance. We found that singing humpback whales perform stereotyped dives that are tightly linked to their acoustic performance. We also recorded song fragment production before the start of a song session in two likely immature individuals (minimum age < 5), while no mature individuals produced song fragments. Overall, this dissertation presents fine-scale behavioral data that fills gaps in the developmental trajectory of humpback whales, providing important insight on this vocal learning mammal.
Access
Open Access
Recommended Citation
Zeh, Julia Marie, "Investigating vocal development in humpback whales: Caller identification, acoustic and movement behavior, and comparisons across age" (2024). Dissertations - ALL. 1910.
https://surface.syr.edu/etd/1910
