Spelling suggestions: "subject:"dolphin.""
41 |
Social play as a tool for developing social-cognitive skills in a wild population of Atlantic spotted dolphins (Stenella frontalis)Unknown Date (has links)
The purposes of this dissertation were to identify complex social-cognitive behaviors in a population of wild Atlantic spotted dolphins (Stenella frontalis) using long-term video archives and identify developmental trends in those behaviors. Chapter One analyzed calf behavior during foraging events involving maternal teaching in order to identify mechanisms for sharing information between mother and calf... The calves' behavior was affected by the referencing cues, supporting the presence of joint attention and true teaching behavior....Chapter Two observed the altered benthic foraging behavior of juvenile play groups, in which juveniles took turns chasing the fish and using referencing gestures to reference the position of the fish to other individuals during the chase, despite the ability of these young, independent dolphins to catch fish much more quickly and efficiently alson... The third chapter analyzed social object play in which dolphins passed pieces of seaweed between individuals. The data clarified developmental trends in the play, and suggested social-cognitive abilities needed for participation. / by Courtney Elizabeth Bender. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.
|
42 |
Predator Influences on Behavioral Ecology of Dusky DolphinsSrinivasan, Mridula 16 January 2010 (has links)
I developed a spatially explicit individual-based model (IBM) to capture the dynamic
behavioral interaction between a fierce predator (killer whale, Orcinus orca) and a clever
prey (dusky dolphin, Lagenorhynchus obscurus), and to answer the ultimate question of
costs vs. benefits for dusky dolphins when making anti-predator decisions. Specifically, I
was interested in calculating time/distance budgets for dusky dolphins in the
presence/absence of killer whales and the presence/absence of movement and behavioral
rules, which presumably evolved in response to spatial and temporal variations in
predation risk. Results reveal that dusky dolphins rest less, travel more and have
reduced foraging time when killer whales are present. These effects are more
pronounced with increased presence of killer whales. The model suggests that a strong
reason favoring the adoption of short and long-term anti-predator mechanisms is
increased survival resulting from decreased encounters with killer whales. Further, a
mother with calf rests less and travels more when killer whales are present relative to a
dolphin without calf. However, a mother with calf on average, flee shorter distances and
have fewer encounters with killer whales than a dolphin without calf. Thus, despite ecological costs, it makes evolutionary sense for dusky dolphins to adopt anti-predator
rules. Bioenergetic consequences for dusky dolphins with and without calf were
estimated as total energetic costs and foraging calories lost due to low/high presence of
killer whales. I calculated total energy costs as: Foraging costs (FC) Locomotor costs
(LC) (Travel) or LC (Travel) LC (Flee) based on the absence, as well as low/high
presence of killer whales. Foraging costs contributed significantly to total energetic costs
estimated. Travel costs are minimal owing to proximity to deep waters. The total energy
costs were not significantly higher from low or high presence of killer whales for mother
with calf, but increases by about 90 kcal/day for a dusky without calf. However, I
estimate foraging calories lost due to increased killer whale presence is almost 5 times
more for mother with calf. Therefore, it might be important to consider indirect
predation risk effects by social type in future studies on animal bioenergetics.
|
43 |
The social structure, behavior, and occurrence of bottlenose dolphins in relation to shrimp trawlers in Southport, North Carolina /Fleming, Kimberly Hoover. January 2004 (has links) (PDF)
Thesis (M.S.)--University of North Carolina at Wilmington, 2004. / Includes bibliographical references (leaves [40]-44).
|
44 |
The promise of animal language researchHoban, Esmé January 1986 (has links)
Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1986. / Bibliography: leaves 296-314. / Photocopy. / Microfilm. / xii, 314 leaves, bound 29 cm
|
45 |
Top Predator Distribution and Foraging Ecology in Florida Bay, FloridaTorres, Leigh G. January 2007 (has links)
Thesis (Ph. D.)--Duke University, 2007. / Includes bibliographical references.
|
46 |
The dolphin in the literature and art of Greece and RomeStebbins, Eunice Burr. January 1929 (has links)
Thesis (Ph. D.)--Johns Hopkins University, l927. / Vita. Bibliography included in the introduction.
|
47 |
A systematic study of the Delphinidae (Mammalia: Cetacea) using cytochrome B sequences /LeDuc, Richard Gene, January 1997 (has links)
Thesis (Ph. D.)--University of California, San Diego, 1997. / Vita. Includes bibliographical references.
|
48 |
Predator movements in complex geography : spatial distribution and temporal occurrence of low-density bottlenose dolphin communities off western Scotlandvan Geel, Catherina Francisca (Nienke) January 2016 (has links)
The coastal waters off western Scotland are inhabited by two small under-studied common bottlenose dolphin (Tursiops truncatus) communities: the Inner Hebrides and the Sound of Barra (SoB) community. The region is considered for future developments for the marine renewables industry, which have the potential to negatively impact these communities; however the assessment of impacts and the development of plans to minimise these are currently hampered by a lack of knowledge about the dolphin's distribution and residency patterns, and spatial and temporal mobility. Using a variety of research methods (dedicated cetacean surveys and targeted photo-ID trips, acoustic monitoring and the collection of opportunistic photo-ID and sightings data from the general public) the current study examined local dolphin spatial and temporal mobility patterns by investigation of their spatial distribution and temporal occurrence. Collectively, the results revealed the presence of two socially and geographically separated (at least 2006-2013) resident communities which both demonstrated year-round presence and long-term site-fidelity, but maintained different ranging patterns. Long-term presence of individuals from the Inner Hebrides community dated back to 2001 and dolphins from this community ranged widely in nearshore waters throughout the entire currently known communal range, and practically used the entire range throughout the year. The SoB community, on the other hand, appeared to have a more restricted distribution, and appeared female-dominated. Summer censuses of the SoB community revealed annual estimates of ≤15 dolphins, with four individuals first identified in 1995, and at least eight calves born since 2005. Acoustic presence of dolphins in the SoB varied through the year, and in relation to the tidal and diel cycles. This study demonstrated that the integration of complementary methodological approaches is useful in investigating mobility patterns of low-density populations, and given the indications for social and spatial isolation, these communities should be managed independently.
|
49 |
Etnoecologia de cetaceos em comunidades de pescadores de São Sebastião, São Paulo / Ethnoecology of cetaceans in fishing communities of São Sebastião, São PauloSouza, Shirley Pacheco de 26 February 2007 (has links)
Orientador: Alpina Begossi / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-09T03:00:31Z (GMT). No. of bitstreams: 1
Souza_ShirleyPachecode_M.pdf: 5428948 bytes, checksum: dc23c6596ba1f8a6197fa96451adfbb1 (MD5)
Previous issue date: 2007 / Resumo: A Etnobiologia estuda as interações entre populações humanas e recursos naturais, enfocando a percepção e o conhecimento humano sobre os recursos naturais, a forma como estes são utilizados e as práticas de manejo desenvolvidas pelas sociedades. O conhecimento ecológico local (LEK, de 'local ecological knowlegde¿) tem sido muito útil na elaboração de sistemas de co-manejo envolvendo comunidades locais, instituições do governo e cientistas. Pesquisas sobre o conhecimento dos pescadores em relação à ecologia de baleias e golfinhos iniciaram-se no Brasil na década passada. Os principais objetivos deste estudo são registrar e avaliar o conhecimento dos pescadores de São Sebastião, litoral paulista, em relação à etnotaxonomia (classificação e nomenclatura) de cetáceos, bem como sobre a etnoecologia destes animais obtendo informações sobre áreas de ocorrência, habitat, sazonalidade, dieta, tamanho de grupo, reprodução, predadores e interações com a pesca. Os resultados demonstraram que os pescadores estudados percebem os cetáceos em função de sua saliência morfológica e cultural. As espécies mais reconhecidas e nomeadas por eles foram as de maior tamanho (Eubalaena australis, Tursiops truncatus), as acidentalmente capturadas em redes de espera (Pontoporia blainvillei, Sotalia guianensis) e as mais veiculadas em programas de televisão (Megaptera novaeangliae, Orcinus orca). Encontramos uma alta concordância entre o LEK dos pescadores estudados sobre a ecologia dos cetáceos, o conhecimento de pescadores de outras comunidades do sul e sudeste brasileiro, dados obtidos de pesquisas locais e da literatura científica. Isto demonstra que o conhecimento dos pescadores pode ser útil para a conservação dos cetáceos, especialmente das espécies pouco conhecidas, sugerindo novas linhas de pesquisa e apontando áreas críticas em relação à captura acidental destes animais. Além disto, os pescadores podem contribuir de forma valiosa na elaboração de estratégias alternativas em relação ao uso de redes de pesca, ao passo que sua participação em projetos e planos de manejo pode ser uma forma de valorização da cultura local / Abstract: Ethnobiology, a branch of Human Ecology, is the study of the interactions between human population and natural resources, concerning human perception, knowledge, resource uses and management. Local ecological knowledge (LEK) has been empirically built by several human societies and transmitted through generations, shaping their culture. LEK has been especially useful
to design systems of co-management involving local people, government institutions and scientists. Surveys on fishers¿ knowledge about cetaceans¿ ecology are relatively scarce around the world and in Brazil they have begun in the last decade. The main objectives of this study are to record and to evaluate the knowledge of the fishers from São Sebastião, in relation to cetaceans¿ folk taxonomy
and bio-ecological aspects, recording their information about classification, nomenclature, occurrence areas, habitat, seasonality, diet, group size, reproduction, predators and interactions with fisheries. Our results showed that fishers¿ perception about cetaceans was highly influenced by phenotypic and cultural salience of the whales and dolphins. The most recognized and cited species were those of greater size (Eubalaena australis, Tursiops truncatus), the most frequently caught ones (P. blainvillei and S. guianensis) and the most exposed by media (M. novaeangliae and O. orca). The high concordance among the LEK of the fishers from São Sebastião on cetaceans, the knowledge of fishers from other communities of southern and southeastern Brazil, data obtained by local researchers and from literature indicates that fishers¿ knowledge could contribute to cetacean¿s conservation, especially in relation to the less studied cetacean¿s species, pointing out new lines of investigation as well as determining fishing grounds where incidental capture of cetaceans are more critical in the studied areas and indicating possible changes in gillnets operations in order to reduce cetaceans catches. Besides, fishers¿ participation in such researches and co-management plans can be a way to revive and valorize their local culture / Mestrado / Ecologia / Mestre em Ecologia
|
50 |
Age, growth, reproduction and sexual dimorphism of the striped dolphin, Stenella coeruleoalba, off the south-east coast of southern AfricaBishop, Amy Ruth January 2014 (has links)
The striped dolphin, Stenella coeruleoalba, is an oceanic dolphin found worldwide in tropical to warm temperate waters. Globally populations are threatened through direct fishing, bycatch and pollution. Little is known about the life history of this species in South African waters and it is currently listed as ‘Data Deficient’ by the International Union for Conservation of Nature (IUCN). Critical to the conservation and management of this species is an understanding of basic life history parameters. For the present study, metadata and tissues from 101 stranded S. coeruleoalba along the south-east coast of southern Africa between 1969 and 2012 were analyzed to examine age and growth, male and female reproduction and sexual dimorphism. Age and growth were determined by counting the number of growth layer groups (GLG’s) present in their teeth. A von Bertalanffy growth curve gave the best fit to the data and indicated that physical maturity was reached around 21 years in males and 18 years in females. Additionally, asymptotic lengths were reached at 231cm and 224cm in males and females, respectively. The maximum ages obtained were 21 years for males and 20 years for females. Length at birth was estimated to be between 116cm and 119cm for males and between 112cm and 114cm for females. The reproductive status of the adult dolphins was assessed by histological and macroscopic analyses of gonadal tissue. Sexual maturity was attained before physical maturity in both sexes. The males reached sexual maturity between 8 and 12 years of age and between 209 and 224cm in total body length. The maximum combined testis weight comprised about 0.24% of the total body weight and sexual maturity was reached between a combined testis weight of 16 and 41g, a mean testis length of 8 and 10cm, and a mean seminiferous tubule diameter of 44 and 70μm. Females attained sexual maturity between 7 and 8 years of age and between 213 and 216 cm in total body length. The ovulation rate was 0.32 per year and the majority of ovulations occurred in the left ovary, with ovulations occurring in the right ovary only in individuals older than 10 years of age. The annual pregnancy rate was calculated to be 26%. Reproductive seasonality could not be established due to the small sample size and the absence of samples throughout the year. However, both conceptions and births appear to occur in both August and December/January. Additionally, testis weight and seminiferous tubule diameters appear to fluctuate throughout the year, which could suggest reproductive seasonality in this species. Sexual size dimorphism in mature adults was evident for a number of external measurements, however, sexual shape dimorphism was not present in this species. Mature males had significantly longer and wider pectoral fins, dorsal fins and flukes than females (p<0.05 in all cases). It was suggested that the larger appendages are required for male on male combat during intraspecific competition for females. Additionally, larger appendages aid in thermoregulation, propulsion and maneuverability. Females had a significantly greater distance between the tip upper jaw and the genital aperture and anus, which was expected due to differences in anatomy between male and female genital openings. Overall, S. coeruleoalba did not exhibit distinct sexual dimorphism and together with the relatively small testes in relation to the total body weight (0.24%) it was proposed that this species demonstrates a less extreme form of polygyny. Additionaly, the results of this study are important to the understanding of the basic biology of the species.
|
Page generated in 0.293 seconds