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Sperm Whale

Page history last edited by PBworks 16 years, 2 months ago
Its elongated head gives it a very distinctive profile and makes up about one third of the animals total length. Fewer than 100 have stranded on British shores in the last 100 years, although strandings are more common than in other large whales. Refloating is possible but extremely difficult as males can be up to 20m long and weigh up to 60 tonnes.
 
 Females are resident in the tropics all year round but the males migrate in search of food and can be seen off the coast of Scotland, particularly around Orkney and the Hebrides. In winter they leave the polar waters in search of warmer conditions, which bring them close to the British shoreline. Unfortunately stormy weather at this time of year makes them incredibly difficult to view by land or boat.
 
Because of their size, they need to feed almost constantly, and food can often be scarce at the surface. Unlike most whales, Sperm Whales are carnivorous and they have adapted to dive to great depths to catch prey of fish, cuttlefish and giant squid – depths of up to 3,000m. They have been known to remain submerged for periods up to 80 minutes as they hunt and feed. In order to exist in these conditions the Sperm Whale has evolved a number of unique physiological features. One third of the whales’ body length is taken up by its head, enlarged by the ‘head case’. This contains an oily substance called Spermaceti, which acts as a buoyancy device and aids diving.
 
 Spermaceti is a liquid at the whales’ body temperature of 33ºC, but it sets to a wax if the temperature falls 2ºC below this. An evolutionary adaptation of the right nostril means the whale can regulate the temperature of the spermaceti when diving. As the whale gets ready to dive, it shuts off the bloodstream to the head case, opens its right nostril and the spermaceti cools, turning it to wax. As a wax it is denser and less buoyant which helps the whale reach the bottom and stay there. When it needs to breathe, it shuts its nostril, opens the blood vessels and the warmth re-converts the spermaceti into oil allowing the whale to return to the surface.
 
 It is also thought that the spermaceti helps aid the identification of prey by concentrating sound emitted by the whale to detect prey (echolocation). The concentrated sounds come together as a loud ‘bang’ and the shock waves produced stun the prey.
 
Although much is known about their physical characteristics very little is known about their behaviour other than echolocation. This is probably because they spend so much time in deep water and they can be hard to track as they can cover thousands of kilometres in a few weeks.

 

 

 

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