SOCIAL STRUCTURE OF THE PILOT WHALES (GLOBICEPHALA MELAS) OFF CAPE BRETON, NOVA SCOTIA, CANADA
The long-finned pilot whale (Globicephala melas) is an intensely social species. I describe the social structure of the population off Cape Breton, Nova Scotia, using 12 years of individual association and behavioural data, adding molecular analyses and investigating alloparental care. Previous stud...
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ftdalhouse:oai:DalSpace.library.dal.ca:10222/72871 2023-05-15T17:54:03+02:00 SOCIAL STRUCTURE OF THE PILOT WHALES (GLOBICEPHALA MELAS) OFF CAPE BRETON, NOVA SCOTIA, CANADA Augusto, Joana Department of Biology Doctor of Philosophy Richard Connor Sophia Stone Timothy Frasier Daniel Ruzzante Hal Whitehead Not Applicable Yes 2017-04-27T14:42:13Z http://hdl.handle.net/10222/72871 en eng http://hdl.handle.net/10222/72871 Social Structure Pilot Whale Globicephala melas Associations Alloparental care Kinship Globicephala melaena Thesis 2017 ftdalhouse 2022-03-06T00:10:16Z The long-finned pilot whale (Globicephala melas) is an intensely social species. I describe the social structure of the population off Cape Breton, Nova Scotia, using 12 years of individual association and behavioural data, adding molecular analyses and investigating alloparental care. Previous studies on the social structure of the species point to pilot whales being organized into social units that associate in labile groups. Units were thought to be matrilineal and comprised of both males and females, with individuals showing bisexual phylopatry. So, social structure for this species was thought to be similar to that of ‘resident’ killer whales (Orcinus orca) in the northwest Pacific. The results of my research suggest a somewhat different structure. I confirmed that pilot whales live in social units comprised of both sexes. I found 21 units in this population, with an average size of 7 individuals. One of the units, the K complex, became very large and started breaking apart over the duration of the study. I found that, over and above membership of the same unit, behavioural state influences how individuals associate with each other. Genetic analysis of microsatellites found no greater relatedness of individuals within the same unit rather than in different units. It seems that unit membership is more fluid than previously thought. I could not assess matrilineality using analysis of mitochondrial DNA due to low haplotype diversity, with only 3 haplotypes identified. I tried to create a model to sex individuals based on dorsal fin shape and photo identification characteristics, but found no correlation between any of those identifiers and individuals’ gender. Alloparental care is common in this population, with more than half the calves being cared for by non-parents. Both sexes care for calves, and carers and calves can be from different social units. There were no cases of reciprocal care, although it is possible reciprocity is occurring outside of the studied 3-year time frame. In conclusion, this population showed some features of social structure that were expected, including the existence of social units, their size and the prevalence of alloparental care. The study also highlighted aspects that were not expected, such as dispersal between units shown by the microsatellite data and a broad distribution of potential alloparental carers for a calf. Thesis Orca Orcinus orca Dalhousie University: DalSpace Institutional Repository Canada Pacific |
institution |
Open Polar |
collection |
Dalhousie University: DalSpace Institutional Repository |
op_collection_id |
ftdalhouse |
language |
English |
topic |
Social Structure Pilot Whale Globicephala melas Associations Alloparental care Kinship Globicephala melaena |
spellingShingle |
Social Structure Pilot Whale Globicephala melas Associations Alloparental care Kinship Globicephala melaena Augusto, Joana SOCIAL STRUCTURE OF THE PILOT WHALES (GLOBICEPHALA MELAS) OFF CAPE BRETON, NOVA SCOTIA, CANADA |
topic_facet |
Social Structure Pilot Whale Globicephala melas Associations Alloparental care Kinship Globicephala melaena |
description |
The long-finned pilot whale (Globicephala melas) is an intensely social species. I describe the social structure of the population off Cape Breton, Nova Scotia, using 12 years of individual association and behavioural data, adding molecular analyses and investigating alloparental care. Previous studies on the social structure of the species point to pilot whales being organized into social units that associate in labile groups. Units were thought to be matrilineal and comprised of both males and females, with individuals showing bisexual phylopatry. So, social structure for this species was thought to be similar to that of ‘resident’ killer whales (Orcinus orca) in the northwest Pacific. The results of my research suggest a somewhat different structure. I confirmed that pilot whales live in social units comprised of both sexes. I found 21 units in this population, with an average size of 7 individuals. One of the units, the K complex, became very large and started breaking apart over the duration of the study. I found that, over and above membership of the same unit, behavioural state influences how individuals associate with each other. Genetic analysis of microsatellites found no greater relatedness of individuals within the same unit rather than in different units. It seems that unit membership is more fluid than previously thought. I could not assess matrilineality using analysis of mitochondrial DNA due to low haplotype diversity, with only 3 haplotypes identified. I tried to create a model to sex individuals based on dorsal fin shape and photo identification characteristics, but found no correlation between any of those identifiers and individuals’ gender. Alloparental care is common in this population, with more than half the calves being cared for by non-parents. Both sexes care for calves, and carers and calves can be from different social units. There were no cases of reciprocal care, although it is possible reciprocity is occurring outside of the studied 3-year time frame. In conclusion, this population showed some features of social structure that were expected, including the existence of social units, their size and the prevalence of alloparental care. The study also highlighted aspects that were not expected, such as dispersal between units shown by the microsatellite data and a broad distribution of potential alloparental carers for a calf. |
author2 |
Department of Biology Doctor of Philosophy Richard Connor Sophia Stone Timothy Frasier Daniel Ruzzante Hal Whitehead Not Applicable Yes |
format |
Thesis |
author |
Augusto, Joana |
author_facet |
Augusto, Joana |
author_sort |
Augusto, Joana |
title |
SOCIAL STRUCTURE OF THE PILOT WHALES (GLOBICEPHALA MELAS) OFF CAPE BRETON, NOVA SCOTIA, CANADA |
title_short |
SOCIAL STRUCTURE OF THE PILOT WHALES (GLOBICEPHALA MELAS) OFF CAPE BRETON, NOVA SCOTIA, CANADA |
title_full |
SOCIAL STRUCTURE OF THE PILOT WHALES (GLOBICEPHALA MELAS) OFF CAPE BRETON, NOVA SCOTIA, CANADA |
title_fullStr |
SOCIAL STRUCTURE OF THE PILOT WHALES (GLOBICEPHALA MELAS) OFF CAPE BRETON, NOVA SCOTIA, CANADA |
title_full_unstemmed |
SOCIAL STRUCTURE OF THE PILOT WHALES (GLOBICEPHALA MELAS) OFF CAPE BRETON, NOVA SCOTIA, CANADA |
title_sort |
social structure of the pilot whales (globicephala melas) off cape breton, nova scotia, canada |
publishDate |
2017 |
url |
http://hdl.handle.net/10222/72871 |
geographic |
Canada Pacific |
geographic_facet |
Canada Pacific |
genre |
Orca Orcinus orca |
genre_facet |
Orca Orcinus orca |
op_relation |
http://hdl.handle.net/10222/72871 |
_version_ |
1766161768374075392 |