Tuesday, May 8, 2012

Life of Pygmy Right Whale

 
Life of Sea | Pygmy Sperm Whale (Kogia breviceps) | Pygmy sperm whales are known from deep waters (outer continental shelf and beyond) in tropical to temperate zones of all oceans to warm. They seem to occur more frequently at or near the continental slope, although they also occur in very deep oceanic regions. Pygmy sperm whales are found in tropical and temperate waters of the Atlantic, Pacific and Indian Oceans. But they are rarely observed at sea, so most data comes from stranded animals - making an accurate range and migration map difficult. 

 
Pygmy sperm whales are extremely difficult to detect, except in very calm sea. These animals have a very unusual shape of the body, which in some respects is similar to that of a small sperm whale. They are very robust, and are not as streamlined as most other odontocetesPygmy sperm whales have a shark-like head with a narrow underslung lower jaw. The head is more square in older persons. The small flippers are far to the front set on the sides in the vicinity of the head. The small dorsal fin is usually set far behind the middle of the back. The dorsal fin is usually strong, sickle-shaped with the tip well below the highest point. Pygmy sperm whales are counter shaded, ranging from dark brown or black on the back to white below. Usually a darker patch encircles the eye. Often the stomach has a pink tone. There is a light colored bar brand called the "false Gill," along the side of the head between the eye and the flipper. It is believed that this is an adjustment related to imitation of their shark predators. 

 
Pygmy and dwarf sperm whales can be rather difficult to distinguish at sea. Pygmy sperm whales grow to slightly larger total lengths, and have smaller, rounded dorsal fin, generally further back on the body. The position of the blowhole is a good indicator. There is some overlap in most of the properties of these two types of identification and to be made carefully, even with a model "in the hand." It's probably best to leave it up to confirm identifications experts who have extensive experience with both species in the genus. Stranded animals, genetic or biochemical analyzes may be necessary to distinguish two types of Kogia. 

 
Most sightings of Pygmy sperm whales from small groups of less than five or six people. Almost nothing is known of the behavior and ecology of this species, except what has been learned from short observations during the research cruises. They are generally not seen in life at sea, but they are among the most frequent small whales stranded in some areas. This may be due to the fact that they are easily missed at sea and rarely in otherwise calm sea. At the sight of the sea, they usually seem slow and sluggish, and often montionless smooth the surface with no visible blow. They just sink out of sight, or can roll to dive (especially if startled).
 
Scientific classification
Kingdom:     Animalia
Phylum:     Chordata
Class:     Mammalia
Subclass:     Eutheria
Order:     Cetacea
Suborder:     Odontoceti
Family:     Kogiidae
Genus:     Kogia
Species:     K. breviceps


Studies of dietary habits based on stomach contents of stranded animals, indicate that this species feeds in deep water, mainly on cephalopods and, less often, deep-sea fish and shrimp. In South Africa, they take at least 67 different prey species, and appear to feed in deeper water than do whales. Pygmy sperm whales can also emit a reddish brown liquid from the anal area when startled. They do not show their tail on diving. They are at least occasionally attacked by sharks and killer whales. 

 
Births usually occur from March to August, and females can reproduce annually. There is evidence that sperm competition may be important in male reproductive success. In some areas, such as the southeastern United States (especially Florida) and South Africa, Kogia whales are among the most stranded marine mammals. This indicates that they may be more common than their low frequency observation suggests. Studies in South Africa, shows that they are not long-lived animals, and the maximum lifetime is known only 23 years. Recent genetic studies suggest a gene flow between the Atlantic and Indian Oceans.

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