A sea elephant rarely deceives
Ten centimetres of blubber: a blessing and a curseLike all true seals, elephant seals have atrophied hind limbs (the equivalent of our legs). Each “foot” is quite distinctive, however, and has a palm which is intended for propulsion in water. On the other hand, they have become unsuitable for any kind of movement on land. Movement on the beach is by means of the flippers, these “arms” are used as supports to enable them to propel themselves on land by making a succession of small bounds. They can move quickly over short distances in this way whether to return to water, catch up with a female or chase away an intruder. The elephant seals possess a thick layer of blubber under their skin, which insulates them against the cold, improves their buoyancy and constitutes a very precious reserve of energy for periods of fasting on land. This blubber, which can reach a thickness of ten centimetres, was the reason these animals were intensively hunted from the 18th century which almost culminated in the disappearance of the species by the end of the 19th century. The seal ships pursued the elephant seals on land during the reproductive period, slaughtered them in great numbers and melted down their sub-cutaneous blubber in order to transform it into an oil of very high quality, which was suitable for use in the softening of leather and the lubrication of machines at the beginning of the industrial revolution. The hunting never really stopped until new kinds of oil of mineral origin took the place of the melted blubber. Since the beginning of the 20th century, the northern elephant seals have been protected by American and Mexican laws, which have allowed their population to grow again to more than 120,000 individuals, even though the species was on the brink of extinction. But the current population, built up again on the basis of a reduced genetic diversity, is probably less robust and more sensitive to diseases and effects of pollutants. |
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© 2007 ULi�ge
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