Cast ashore final paper

Cast ashore final paper - Beck 1 A "strand" is a...

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Beck 1 A “strand” is a beach or land bordering a body of water, and stranding is defined as running aground. The term stranded also refers to any creature left in a helpless position, such as a marine mammal that comes ashore ill, weak, or simply lost (Geraci and Lounsbury 2005). This paper will discuss mass strandings in marine mammals, the general biology of the marine mammals that mass strand, and the theories as to why they strand. Single strandings are more common than mass strandings, with the cause of them typically being poor health, parasites, wounded or orphaned (Prescott et al. 1979). The cause of mass strandings, however, is much harder to determine and is still puzzled over today. A mass stranding is defined as an event in which two or more individuals of the same species, not including a single cow-calf pair, beach within a close distance to one another (Dierauf and Gulland 2001). It is mainly the odontocetes that are involved in mass strandings, and among them a few species predominate; these include: long and short finned pilot whales Globicephalus melas and Globicephala macrorhynchus , the false killer whales Pseudorca crassidens, sperm whales Physeter macrocephalus, and the Atlantic white sided-dolphin Lagenorhynchus acutus (Prescott et al. 1979) . Another species that has shown up more recently in mass strandings is the Cuvier’s beaked whales Ziphius cavirostris. Some of the theories as to why marine mammals mass strand include: social structure, complex topography, geomagnetic anomalies, disease or injury, or acoustic disturbances. The biology of the animals that strand can provide clues as to why these marine mammals are typically involved in mass strandings. The long and short-finned pilot whales (Globicephalus melas and Globicephala macrorhynchus) get their name from a belief that a single member of a pod pilots, or leads the group, and that the others
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Beck 2 continue to follow, even when it means certain death (Reeves et al. 2002). They have a rather bulbous shaped head, a barely noticeable beak, a color pattern of typically dark gray to black with tapering white or a light gray streak behind the eye, and either short or long flippers, depending on the species. They are extremely social animals and can be found in pods that number in the hundreds to thousands (Reeves et al. 2002). The false killer whale was thought to be an extinct species until 1861, when a school of them stranded in Germany (Reeves et al. 2002). It has a slender dark body, with a small, rounded or conical head. It is similar to the killer whale (Orcinus orca) in some aspects, mainly with the teeth, however, the false killer whale is not known to use their teeth on mammalian prey as the killer whale does. Strandings of false killer whale’s can involve hundreds of whales and can result in the eradication of entire schools (Reeves et al. 2002). The sperm whale is the largest of the toothed whales and is one of the deepest and
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This note was uploaded on 05/01/2008 for the course AVS 460x taught by Professor Colleen during the Spring '08 term at Rhode Island.

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Cast ashore final paper - Beck 1 A "strand" is a...

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