|dc.contributor.author||Shapiro, Ari D.||
|dc.description||Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2008||en||
|dc.description.abstract||Studying the social and cultural transmission of behavior among animals helps to
identify patterns of interaction and information content flowing between individuals. Killer
whales are likely to acquire traits culturally based on their population-specific feeding
behaviors and group-distinctive vocal repertoires. I used digital tags to explore the
contributions of individual Norwegian killer whales to group carousel feeding and the
relationships between vocal and non-vocal activity.
Periods of tail slapping to incapacitate herring during feeding were characterized by
elevated movement variability, heightened vocal activity and call types containing additional
orientation cues. Tail slaps produced by tagged animals were identified using a rapid pitch
change and occurred primarily within 20m of the surface. Two simultaneously tagged
animals maneuvered similarly when tail slapping within 60s of one another, indicating that
the position and composition of the herring ball influenced their behavior.
Two types of behavioral sequence preceding the tight circling of carousel feeding
were apparent. First, the animals engaged in periods of directional swimming. They were
silent in 2 of 3 instances, suggesting they may have located other foraging groups by
eavesdropping. Second, tagged animals made broad horizontal loops as they dove in a
manner consistent with corralling. All 4 of these occasions were accompanied by vocal
activity, indicating that this and tail slapping may benefit from social communication. No
significant relationship between the call types and the actual movement measurements was found.
Killer whale vocalizations traditionally have been classified into discrete call types.
Using human speech processing techniques, I considered that calls are alternatively
comprised of shared segments that can be recombined to form the stereotyped and variable
repertoire. In a classification experiment, the characterization of calls using the whole call, a
set of unshared segments, or a set of shared segments yielded equivalent performance. The
shared segments required less information to parse the same vocalizations, suggesting a more
parsimonious system of representation.
This closer examination of the movements and vocalizations of Norwegian killer
whales, combined with future work on ontogeny and transmission, will inform our
understanding of whether and how culture plays a role in achieving population-specific
behaviors in this species.||en||
|dc.description.sponsorship||Funding sources: The Ocean Life Institute at WHOI and the National Geographic Society, the National Defense Science and Engineering Graduate Fellowship, a National Science Foundation Graduate Fellowship, the Academic Programs Office at WHOI and Dennis McLaughlin at MIT.||en||
|dc.publisher||Massachusetts Institute of Technology and Woods Hole Oceanographic Institution||en||
|dc.subject||Social behavior in animals||en_US||
|dc.title||Orchestration : the movement and vocal behavior of free-ranging Norwegian killer whales (Orcinus orca)||en||