A small lemur offers itself as a model of torpor
In Brunoy, in Essonne, it is called “the little castle”. A large 18th century bourgeois housee as there are dozens of them, in these municipalities of Ile-de-France located about thirty kilometers from Paris. With its park, its outbuildings, and even a street named after it. Except that, since 1926 and a legacy, the house has been home to laboratories of the National Museum of Natural History. Plants, trees, insects, birds spread out there at leisure. But the most surprising thing is undoubtedly the breeding of nearly 500 mouse lemurs installed in the ba*****t of the house. Since the 1960s and the return of expeditions to Madagascar, researchers from the Museum have been studying this 50-gram lemur there in an attempt to unlock its many secrets, starting with that of torpor.
Because if, during the summer, the mouse lemur shares the way of life of many lemurs – arboreal, omnivorous, nocturnal – during the winter, it spends its day hidden at the bottom of a tree hole in a state of torpor. deep. “It’s not exactly hibernation, since every night it returns to its normal state.explains researcher Jérémy Terrien. Its size would not allow it to build up enough reserves to chain weeks of torpor. But, otherwise, it adopts the same strategy to save its resources, hypometabolism, and copies its rhythm to that of the seasons. »
Because if the Malagasy winter certainly does not resemble the climate encountered by the marmots of the Alps, the bears of Sweden or the ground squirrels of Alaska, the resources in water and food (fruits, insects) are also rarefied there. Also the mouse lemur begins by preparing and takes 50% of weight in a few weeks. It stores fat in various parts of its body, starting with its tail.
“Look at that little sausage! » Jérémy Terrier has just opened a large cage and plunged his hand into one of the shelters hung inside. The afternoon is coming to an end, the animal he has seized is waking up. His big eyes scrutinize us. Behind him, his swollen tail looks almost cumbersome. The animal facility has been divided into six sectors which follow, staggered, the different seasons of the year, thus offering researchers great flexibility in their work. And in the sector visited today, temperatures and photoperiod correspond well to winter on the Indian Ocean island. End of winter, more exactly, as evidenced by the ********s of the males, which begin to regain volume, after several months of almost total retraction. Barely released, the animal runs, jumps from one laurel branch to another, grabs a string, climbs into a basket… “They are very active and can bite violently”warns the researcher, closing the cage and removing the protective glove he had put on.
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