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Hares Fell Trees

29.01.2003


It seems that biologists know everything about the Alpine hare (Lepus timidus), particularly about its ration. However, the Yakut scientists, Anatoly Pshennikov and Vladimir Pozdnyakov have discovered a previously unknown method the hares employ in wintertime when they suffer from the lack of food.

Forage is scarce in winter in Yakutia. The Alpine hares are content to feed on bushes and young trees. If the distance between the ground and a thin twig is less than a meter, the hare bites it off. This is the best food the hare can count on in wintertime. Thin sprouts make quick and substantial food for hares (1 gram of forage per 40-45 seconds). When there are no twigs available within their reach, the hares make a ’ring’ on the tree, gnawing the rind and bast round the trunk. Sometimes a thin tree fails to stand it and falls down, and then the hare gets tasty twigs. If young trees are gnawed round, the hares have to feed on the rind of old trees, although this does not happen often. These are the traditions of the hare nutrition.

Nevertheless, hunger can make the animals change their ration. If the hares happen to find hay - they feed on hay. Once, in place of such stack there remained only a circle of hare excrement 7-10 centimeters high along the perimeter, hay-dust mixed with excrements lying in the middle. Sometimes the hares nibble tar, polyethylene, tarpaulin. The hunters from the town of Verkhoiansk used to tell about the cases when the hares were eating their entrapped congeners. However, there is one more way of getting food - an unconventional method of getting traditional forage. To get hold of tasty thin twigs, the hares purposefully fell trees.



The animals can cope with the trunks up to 4.5 meters in diameter. In different areas of Yakutia they deal with willows, alders, birches and larches. The hares fell the trees and normally gnaw away all young sprouts and twigs, but the rind often remains intact as it is less tasty. In other words, the hares picked up the method of food procurement the beavers employ. Unlike the beavers nibbling the trees taper off, the hares do not gnaw the trunks round, but do that on one side. The animals have to gnaw out up to 8 to10 cubic centimeters of dead wood which they normally avoid. On the opposite side of the trunk a thin narrow layer of rind and bast remains intact, the fallen tree often hanging by this layer. Sometimes such feeding transforms thick shoots of young trees into a control line: the stakes pointed up by the hares protrude from the ground, the stakes being several dozens of centimeters high, and the gnawed around trunks hang down from them resting against the ground.

The new method evidently brings advantages. The hares capable of felling small trees will stand better chances for of survival as they get access to high horizons of stand. In Central Yakutia willows and birches of 3 to 4 centimeters in diameter can grow up four meters high. By felling such a tree, the hare gets about half a kilogram of thin twigs and nearly the same amount of rind and bast, i. e. a hare’s daily ration.

In 1988 the Yakutsk researchers first came across such a peculiar way of getting
food. Such cases have not been described in published materials, but the scientists believe that this is not due to novelty of the method but because it is extremely rare. The hares are engaged in felling the trees only in case of extraordinary lack of food. Otherwise, the researchers have to assume that the Alpine hare population in Yakutia has given birth and accumulated the hares possessing a new tactics for obtaining food. Should the new tactics be consolidated, that will provide absolutely new opportunities for the species survival in extreme conditions and for developing new territories.

For additional information: +7 (411-2) 445-690; Fax: + 7 (411-2) 445-812; +7 (411-2) 241-290 or aepsh@mail.ru; lena-nord@sterh.sakha.com

Natalia Reznik | Informnauka
Further information:
http://www.informnauka.ru/eng/2003/2003-01-28-02_304_e.htm

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