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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Communication in the yellow mongoose, Cynictis penicillata

Le Roux, Aliza 12 1900 (has links)
Thesis (PhD (Botany and Zoology))--University of Stellenbosch, 2007. / Improved anti-predator protection has been postulated to be the primary advantage of sociality in the family Herpestidae. Therefore, the yellow mongoose, Cynictis penicillata, is considered an anomaly in the family because it may den socially with conspecifics, cooperating in the rearing of young and territory defence, but inevitably forages alone. I studied the communicative and anti-predator behaviour of a population of yellow mongooses which exhibited a lower degree of sociality than populations studied elsewhere. The yellow mongoose’s flexible social nature was evident in its vocal repertoire. Although its vocal repertoire was smaller and less context-specific than those of social mongooses, it had a large proportion (over 50%) of affiliative vocalizations, suggesting that individuals show a higher degree of cooperation than strictly solitary species. During predator encounters yellow mongooses used a simple urgency-based alarm call repertoire, indicating high and low urgency threat with two separate call types. The social environment strongly affected the alarm communication of yellow mongooses – vocal alarms were displayed almost exclusively by individuals in a group, whereas the visual alarm (a raised tail) was displayed by solitary individuals, when predators were outside the range from which they were potentially dangerous. This was a clear demonstration of the ‘audience effect’ – a phenomenon whereby animals adjust their communicative signals depending on the audience that is present. Until this study, the audience effect has only been demonstrated in obligate social species. The yellow mongoose’s social flexibility was further reflected in its territorial scent marking behaviour. In contrast to high density populations, where subordinate individuals contribute significantly to territory defence and scent marking, only the dominant male marked and defended territory borders in this low density population. Dominant males appeared to overmark the small number of cheek marks that females deposited, especially during the breeding season, which suggests that cheek marks were used in mate guarding. The yellow mongoose showed less flexibility in responses to conspecifics while foraging: the presence of group members appeared to make foragers more nervous, as individuals increased vigilance and decreased foraging success when group members were nearby. This could not be attributed to foraging competition, which happened very rarely. Yellow mongooses relied on a form of vigilance that allowed them to continue foraging while remaining alert, which contrasted with meerkats, Suricata suricatta, that had to interrupt foraging in order to be vigilant. The foraging patterns of yellow mongooses and meerkats differed markedly, and both species appeared to be inflexible in these patterns. I have proposed, therefore, that rigid vigilance patterns of vigilance are the reason why yellow mongooses forage alone, despite showing other cooperative tendencies. This study highlights that the selective forces acting on group living and group foraging are very different, and that the group-size effect – which postulates that individual vigilance declines as group size increases – may not be applicable to species adapted to solitary foraging.
62

interunit, environmental and interspecific influences on silverback-group dynamics in western lowland gorillas (Gorilla gorilla gorilla)

Klailova, Michelle January 2011 (has links)
While a major benefit of female-male associations in gorillas is protection from infanticidal males, a silverback is also responsible for providing overall group stability and protection from predation and other environmental or interspecific risks and disturbances. A silverback’s reproductive success will be a function of his group’s survival, his females’ reproductive rates and the survival of his progeny. Here, I evaluate the western lowland silverback’s role as the protective leader of his group and provide the first detailed behavioural study of silverback-group dynamics for western lowland gorillas from a holistic perspective; in both forested and bai environments, from nest-to-nest. Behavioural data were collected from one single-male habituated western lowland gorilla group, over 12-months starting January 2007 at the Bai Hokou Primate Habituation Camp, Central African Republic. Data collection - instantaneous scans, continuous written records of all auditory signals, nesting data, and ad libitum notes on interunit interactions - focused on the silverback and those individuals in his immediate proximity. Analyses were conducted over 258 morning or afternoon sessions, on 3,252 silverback behaviour scans (plus 1,053 additional smell scans), 22,343 auditory signals and 166 nest sites. Evidence from neighbours to the silverback, group spread, progression, ranging, nesting, human directed aggression and silverback chemosignalling analyses suggest that silverback-group dynamics have developed complex, strategic spatial and social strategies to cope with perceived risk in rainforest environments, which respond to differing habitats, and differing intensities of interunit interactions and interspecific disturbance. I also show that the release of pungent extreme and high level silverback odours may function as both acute and chronic indicators of arousal designed to intimidate extragroup rival males and attract adult females by expressing dominance, strength, and health. Higher level silverback odours may also provide cues for group members to increase vigilance in risky situations, whereas low level smells may function as a baseline identification marker and provide both self and intragroup reassurance. Western lowland silverback-group relationships appear to be centred on providing a strong protective – rather than socially interactive - and stabilizing role to ensure group cohesion and safety, which ultimately increases the likelihood of male reproductive success.
63

A study on elephant and human interactions in Kodagu, South India

Narayana, Malavika Hosahally January 2014 (has links)
Increasing human populations have resulted in the extensive conversion of natural forests and range lands into agricultural lands, resulting in an expansion of the interface between people and elephants across the elephant range countries of Asia and Africa. This interface describes the nature of two-way interactions between people and elephants, which can be positive and reverential or hostile and negative. Elephant crop-raiding, one of the most negative interactions for people at the interface, is not only the result of decreased food resources and space, but has also been attributed to a preference for cultivated crops and to damage caused during elephant movements between habitats. The aim of this thesis was an attempt to understand the use of coffee agroforestry areas by elephant populations in a South Indian district, Kodagu, and to assess the risks to elephants and people of coffee plantations. Geographically, located at a significant position in the Western Ghats, Kodagu district is a part of one of the largest wild Asian elephant ranges harbouring India’s largest elephant population. Kodagu has a unique topography and coffee agroforestry system in considered as the boon for conservation. This thesis is the first long term (one year) study on the elephant populations using coffee estates in Kodagu. Crop-raiding events across Kodagu and their intensity of occurrence were determined from the Forest Department compensation records. Virjapet taluk was one of the three administrative units of Kodagu with frequent incidences of crop-raiding, including elephant mortality and human deaths. High rates of crop-damage in Virajpet included both coffee and paddy rice produce as the land is conducive for the cultivation of both. To understand the use of coffee estates by elephants, coffee estates in Virjapet were directly and indirectly monitored for the presence of elephants using dung sampling (N=202), camera trapping, video and photo documentation, as well as sightings (N=408) and reports by local workers, in order to identify the individuals or groups of elephants frequenting these coffee estates. Lone male and all male groups used coffee estates most frequently and family herds ranging in group size from 2 to 10 were present mainly during the peak season of coffee ripening (post monsoon). Presence of large numbers of elephants, especially with large female groups, was associated with crop-damage during the months of December-January. As seasonal movements of elephants in Kodagu districts are still not known, it is unclear why the number of elephants in coffee estates post-monsoon increases when food availability should also be higher in forests. These large coffee estates were used as refuge areas by elephants during the day by all individuals and groups, and feeding on estates occurred during the night to early morning hours. Dung analysis and observations suggested that coffee estates were attractive for elephants due to the constant availability of water (for irrigation), green fodder, and cultivated fruit trees, especially jackfruit. Coffee plants were damaged both due to consumption (47% of dung samples in this study) and accidental damage during elephant movements within the estates. Although the dung sampling could not confirm whether coffee had become a novel food resource, the presence of large number of elephants during the coffee ripening season suggested that the potential for coffee berries to be added regularly to the diet in the future, with potential consequences for coffee invasion of native forests through dung seed dispersal. People working on large coffee estates were accustomed to the presence of elephants and were generally knowledgeable of the areas that elephants frequented, thus avoiding fatal encounters. However, safety of farmers and other people working on the estates remains a major concern, especially for large coffee estates owners. The constant interaction between elephants and people also led to more negative perceptions of elephants, and reduced the tolerance of elephants in the area. The unique topography of Kodagu as a mosaic of forests and farms challenges the number of possible mitigation methods to prevent negative encounters between people and elephant. The elephants of Kodagu may have adapted behaviourally to the presence of people, but long-term monitoring of the elephant population is important to understand their ecological and social adaptations to the various costs and benefits of using this agroforestry landscape. Suggestions for management of the elephant-human interface and mitigation of negative attitudes and actions were made, through a model that incorporates a multiple stakeholder (including elephants) action plan.
64

Parameters impacting the reproductive fitness of Tursiops truncatus (Atlantic bottlenose dolphin): interactions between native endocrinology and endocrine-disruptors

Unknown Date (has links)
Persistent, anthropogenic contaminants collectively known as endocrine-disrupting chemicals (EDCs), are considered to be potential threats to wildlife reproductive fitness (Wingfield, 2002). The modes by which EDCs act on the reproductive system, and establishment of steroid profiles in wildlife, are important areas of study. Two means of performing an endocrine snapshot profile from dolphin tissues (serum and urine) were tested on samples, comparing a novel high performance liquid chromatography method to newly-validated enzyme-linked immunoassays (ELISAs). Serum and urine samples were obtained from two marine parks, and from free-ranging dolphins in the Indian River Lagoon (IRL) and Charleston Harbor (CHS) systems. Relative binding affinities of steroids versus putative EDCs to steroid receptors were compared in dolphin reproductive tissues, obtained by the Georgia Aquarium's Dolphin Conservation Field Station (GADCFS) from strained bottlenose dolphins (four male, three female) during 2010 and 20ll.........I conclude that endocrine disruptors are tissue and receptor specific, and both legacy and emerging contaminants are of concern to dolphin stocks, particularly those facing other significant environmental stressors. / by Sharon M. Homer-Drummond. / Vita. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.
65

Personality Traits in Atlantic Spotted Dolphins (Stenella Frontalis): Syndromes and Predictors of Neophilia

Unknown Date (has links)
Personality is defined as inter-individual variation of behavioral traits while maintaining intra-individual stability. The focus of this study was to observe distinct personality trait categories, establish baseline personality trait phenotypes for the juvenile population, and compare the personality phenotypes between different categories, such as sex or generation. Three personality traits were studied—sociability, curiousity, and boldness—based on the percentage of time individuals spent with conspecifics, human researchers, and their mothers, respectively. The surveyed individuals significantly varied positively and negatively from the means of each trait, and no significant difference for any trait was found between males and females, or across time periods. A moderately strong correlation was discovered between two personality traits, boldness and curiousity, suggesting a personality syndrome. The second primary goal was to use the aforementioned baseline to determine if personality traits can be used to predict neophilic behavior specific to human-dolphin communication research. Six of the study subjects were more prone than their peers to engage with the two-way work, and these individuals were more bold—spent less time with their mothers—than the other subjects. This suggests that boldness has some predictive capabilities towards this type of neophilia. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection
66

Chimpanzee alarm communications: a zoosemiotic study

Unknown Date (has links)
Evidence for conceptual semantics is well established in monkeys, however this basis of human language is less evident in the great apes. In order to study semantic communications in chimpanzees, I analyzed alarm calls produced towards a blimp as it was flying overhead. I then replayed a set of these alarm calls to the chimps on a different day. The chimps appeared to act in a manner consistent with the presence of the blimp. The calls they produced in response to the playback stimuli were nearly identical to the calls that were produced during the actual flyover. Though the data collected were not sufficient to support a definitive claim, it does appear that the chimpanzees of the study have a meaning-laden vocalization for the aerial stimuli. Whether this call is specific to the blimp or generalizable to other aerial threats is yet to be determined. / by Alyssa M. Raymond. / Thesis (M.A.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web.
67

Home on the range: spatial ecology of Atlantic spotted dolphins (Stenella frontalis) in the Bahamas

Unknown Date (has links)
I examined summer home range use of Altantic spotted dolphins in the Bahamas from 1991-2004. Home ranges for 86 dolphins using the 95% Fixed Kernel Density (FKD) estimator averages 62.o km2+=22.96 km2 and ranged from 24.8 km2 to 148.4 km2. Older animals and males had the largest ranges. Home range size did not vary with female reproductive status. core areas were defined by the 50% FKD contour and averaged 10.32 km2 +=5.47 km2. Habitat use was different between reproductive states for females. Non-reproductively active (NRA) females used deeped habitat. Behavioral use of the home range varied spatially. The core area was an important foraging area for males and reproductively active females. NRA females foraged more outside their core area compared to the core area. / by Bethany Augliere. / Thesis (M.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.
68

Social learning and social behaviour in two mixed-species communities of tufted capuchins (Sapajus sp.) and common squirrel monkeys (Saimiri sciureus)

Messer, Emily Jane Elizabeth January 2013 (has links)
Primates are known for being highly social species, living in groups of various compositions with different social structures. The study of social or observational learning has largely focussed on investigating non-human primates' abilities to imitate, with a more recent shift towards examining the social context of social learning. This shift has presented opportunities to investigate how the social context of different species affects the diffusion of socially learnt behaviours. In this thesis, I set out to monitor the spread of different experimentally seeded and naturally occurring socially learned behaviours in brown (tufted) capuchin monkeys (Sapajus sp.) and common squirrel monkeys (Saimiri sciureus).These species were selected as they form mixed species groups in the wild, and display marked differences in their social tolerances, thus presenting the opportunity to investigate conspecific and heterospecific social learning in related but differently bonded social groups. My results show evidence of social learning from conspecifics in capuchin and squirrel monkeys, attesting to that already documented in capuchin monkeys and indicating for the first time, that common squirrel monkeys can learn socially. Additionally, I demonstrate that capuchin monkeys are influenced by squirrel monkeys when foraging for food in mixed species groups. Furthermore, although squirrel monkeys are not as socially tolerant as capuchin monkeys, individuals who were better connected within the foraging test area learned experimentally-seeded techniques of models faster and more faithfully. When performing socially contagious anointing behaviours, regardless of tufted capuchin monkeys being influenced by the amount of resources provided for them to anoint with, they still performed more socially anointing than has been previously documented in other captive species, corroborating the levels of social anointing demonstrated in semi-free ranging groups. Further support was found for anointing demonstrating a social bonding and medicinal function in tufted capuchin monkeys.
69

The Role of Social Context in Modulating Gene Expression, Neural Activity, and Neuroendocrine Response in Individuals of Varying Social Status

Williamson, Caitlin January 2018 (has links)
Social context, which includes both the direct social experience of individuals as well as the characteristics of their social network as a whole, has been shown to be an important modulator of behavior across species. However, relatively little is known about the role of social context in regulating the complex relationships between neurobiology, neuroendocrine response, and behavior in mammals. Historically, the neurobiology of social behavior has been studied at the dyadic level, looking at brief social interactions between pairs of individuals. Given that all social species live in groups, rather than pairs, it is essential that we begin to understand the role social context at the group level plays in regulating physiology. Throughout this thesis, I use a novel behavioral housing system to study how the characteristics of stable social groups and how instances of social opportunity, when individuals are ascending up a social hierarchy, are associated with differential brain gene expression, neuroendocrine output, and behavior. I first extensively analyze the social dynamics of male dominance hierarchies, showing that they are both consistent, in that males reliably form significantly linear dominance hierarchies, and unique, in that the characteristics of these hierarchies vary from group to group. I further prove that mice living in these social hierarchies are extremely socially competent, displaying the ability to respond appropriately to individuals of varying social status. I demonstrate that females are capable of forming dominance hierarchies as well, but that their hierarchies differ from those of males. I then use this foundational knowledge to investigate how these different hierarchy characteristics can lead to differences in physiology, how one’s social status is associated with brain gene expression and neuroendocrine response, and how disruption of a hierarchy through removal of the alpha male leads to robust behavioral as well as physiological consequences. Finally, I use the insights gained from this immediate early gene work to demonstrate the crucial role of the infralimbic/prelimbic region of the medial prefrontal cortex in regulating socially competent response to changing social contexts. Taken together, this work establishes the broad role social context plays in regulating the complex relationships between behavior, brain gene expression, neural activation, and neuroendocrine output.
70

Social behavior and communication in a herd of captive giraffe

Bashaw, Meredith J. 01 December 2003 (has links)
No description available.

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