Social structure and underwater behavior of harbor seals in southern Monterey Bay, California

Nicholson, Teri Elizabeth (2000) Social structure and underwater behavior of harbor seals in southern Monterey Bay, California. Masters Thesis, San Francisco State University, 98pp.

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To understand harbor seal social and mating strategies, I examined site fidelity, seasonal abundance and distribution, herd integrity, and underwater behavior of individual harbor seals in southern Monterey Bay. Individual harbor seals (n = 444) were identified by natural markings and represented greater than 80% of an estimated 520 seals within this community. Year to year fidelity of individual harbor seals to southern Monterey Bay coastline was 84% (n = 388), and long-term associations (>2 yrs) among individuals were common (>40%). Consistent with these long-term associations, harbor seals were highly social underwater throughout the year. Underwater social behavior included three primary types: (1) visual and acoustic displays, such as vocalizing, surface splashing, and bubble-blowing; (2) playful or agonistic social behavior such as rolling, mounting, attending, and biting; and (3) signal gestures such as head-thrusting, fore-flipper scratch~ng, and growling. Frequency of these types of behavior was related to seal age, gender, season, and resource availability. Underwater behavior had a variety of functions, including promotion of learning and social development, reduction of aggression and preservation of social bonds by maintaining social hierarchy, and facilitation of mate selection during breeding season. Social behavior among adult males was significantly correlated with vocalization characteristics (r = 0.99, X2 = 37.7, p = 0.00087), indicating that seals may assess their competition based on underwater vocalization displays and adopt individual strategies for attracting females during breeding season based on social status. Individual mating strategies may include defending underwater territories, using scramble tactics, and developing social alliances. (PDF contains 105 pages)

Item Type: Thesis
Title: Social structure and underwater behavior of harbor seals in southern Monterey Bay, California
Personal Creator/Author:
Nicholson, Teri Elizabeth
Number of Pages: 98
Date: 2000
Department: Moss Landing Marine Laboratories
Institution: San Francisco State University
Additional Information: Copyright permission signed by the author is on file with the IAMSLIC archive.
Subjects: Biology
Item ID: 6823
Depositing User: Joe Wible
Date Deposited: 03 Oct 2011 12:15
Last Modified: 03 Oct 2011 12:15

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