Scientists have discovered that some ring-tailed lemurs in Madagascar regularly retire to limestone¹ chambers² for their nightly snoozes, the first evidence of the consistent, daily use of the same caves and crevices³（裂缝） for sleeping among the world's wild primates⁵. The ring-tailed lemurs may be opting⁶ to sleep in caves for several reasons, said University of Colorado Boulder⁷ anthropology⁸ Associate Professor Michelle Sauther, who led the study. While the cave-sleeping behavior is likely important because it provides safety from potential predators⁹, it also can provide the primates with access to water and nutrients¹⁰, help to regulate their body temperatures during cold or hot weather and provide refuge from encroaching（渐渐渗入的） human activities like deforestation, she said.

 

"The remarkable¹¹ thing about our study was that over a six-year period, the same troops of ring-tailed lemurs used the same sleeping caves on a regular, daily basis," she said. "What we are seeing is a consistent, habitual¹² use of caves as sleeping sites by these primates, a wonderful behavioral adaptation we had not known about before."

 

A paper on the subject appeared in the November issue of the journal Madagascar Conservation and Development. Funding for the project came from Primate⁴ Conservation Inc., the International Primate Society, the American Society of Primatologists, the National Geographic¹³ Society, CU-Boulder, the University of North Dakota, Colorado College and the National Science Foundation.

 

Although sleeping in caves by ring-tailed lemurs -- which are found only in Madagascar -- has likely been going on for millennia¹⁴, it is only now being recognized as a regular behavior, said Sauther. The endangered Fusui langurs, slender, long-tailed Asian monkeys roughly 2 feet tall, also have been documented sleeping in caves but as a direct result of extreme deforestation, moving from cave to cave every few days. There also have been isolated¹⁵ reports of South African baboons¹⁶ sleeping in caves.

 

Ring-tailed lemurs are easily identified by their characteristic, black and white ringed tails, which can be twice as long as their bodies. They weigh roughly 5 pounds with a head-body length of up to 18 inches and are highly social, congregating¹⁷ in groups of up to 30 individuals. Sporting fox-like snouts（鼻子） and slender frames, they are unusual among lemurs, spending a considerable amount of time on the ground feeding on leaves and fruit and socializing, said Sauther.

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