Biogeography of bottlenosed dolphins Research Paper

Biogeography of bottlenosed dolphins - Research Paper Example The large brain size and the vocal learning on one hand are the cause of the organism being a major attraction and a source of amusement, and on the other hand render it vulnerable to noise and chemical pollution resulting from anthropogenic activity. The conservation strategies directed at habitat preservation of the organism are recommended. BIOGEOGRAPHY OF BOTTLENOSE DOLPHINS INTRODUCTION Bottlenose dolphins belong to the order Cetacea, the term derived from Greek word ketos meaning whale. The order includes large aquatic mammals with forelimbs modified into flippers, a horizontally flattened tail, lacking hind limbs and with one or two nostrils. The order includes the suborders Odontoceti (toothed whales) and Mysticeti (baleen whales). Most Dolphins are included in the family Delphinidae, belonging to suborder Odontoceti, including the bottlenose Dolphin or genus Tursiops. The genera Tursiops (derived from Latin word Tursio meaning Dolphin or Dolphin like), has been further class ified to include two species on the basis of biochemical and genetic studies: common bottlenose dolphin or T. truncatus and the Indopacific bottlenose dolphin or T. aduncus (Rice, 18). ... The biogeography of an organism provides significant information regarding its evolutionary history and adaptation. Thus biogeography can be considered to include the spatial as well as temporal distribution of an organism. The common bottlenose dolphin T.trucatus enjoys worldwide distribution including tropical and temperate, inshore, coastal, shelf and oceanic areas (Reynolds et al., 12), except the polar region, northward of 45?, though they do occurs far as 62?N7?W in northern Europe. Found rarely in Baltic Sea and vagrant in Newfoundland and Norway, the species is present is as yet uncertain in other areas. The author aims to present in the current paper an account of the biogeography of the common bottlenose dolphin or T. truncatus; along with the evolutionary history of the organism on the basis of fossil records and the threat to conservation programs for the organism specially those relating to its biogeography. BIOGEOGRAPHY Figure 1 The major distribution areas of common bo ttlenose dolphin (figure 1) include the western margins of North Atlantic where the coastal forms occur within a distance of 5km from the land and in bays and estuaries (Mead and Potter, 165). The offshore forms occur within 200-2000m range along the shelf break in regions north and north east to Georges bank (Kenney, 369); and in the Scotian shelf; with the distribution of the two forms overlapping in some zones. The coastal forms are prevalent throughout the year continuously along the North Carolina to Texas (Mead and Potter, 165). In southeastern US they also occur as communities exhibiting specific association patterns and individual home ranges. In the eastern Pacific region, T. truncatus occurs in the