*This story has been edited to reflect a change.
The image of the lemur, a one-and-a-half-foot long primate with a long tail, is high up in a tree. Recent research from the University of Colorado, however, found that some of the primates actually sleep and live in the limestone caves of Madagascar, e! Science News reported.
Only ring-tailed lemurs, a subspecies of lemur known for their long, black and white tails, have taken to the caves and only ring-tailed lemurs living in spiny forests, where sleep among the tops of trees is uncomfortable, according to esciencenews.com. Scientists surmise the behavior has been going on for millions of years, but only recently have they understood it to be a regular pattern. In fact, ring-tailed lemurs typically choose the same crevice every night of sleep, another behavior that surprised researchers. They're one of the only primates to consistently dwell in caves; other primates, such as Cat ba langors, dwell in the caves of Vietnam. Humans and baboons have also been known to only occassionally take refuge underground and in the rocks though not as regular habbit, according to Science World Report.
"The remarkable 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," said University of Colorado Boulder anthropology Associate Professor Michelle Sauther, leader of the study. "What we are seeing is a consistent, habitual use of caves as sleeping sites by these primates, a wonderful behavioral adaptation we had not known about before."
When Sauther and fellow scientists first began their work in Madagascar, the only region of the world where the species is found, they expected the lemurs to climb down from trees in the morning.
"They seemed to come out of nowhere, and it was not from the trees," Sauther said. "We were baffled. But when we began arriving at the study sites earlier and earlier in the mornings, we observed them climbing out of the limestone caves."
Another reason why ring-tailed lemurs choose caves is to avoid their main predator, a relative of the mongoose known as a fossa. Spiny forests are not only difficult places in which to make a bed, but their easy maneuverability provides open access to beneficiaries like the fossa, according to esciencenews.com.
"We think cave-sleeping is something ring-tailed lemurs have been doing for a long time," she said. "The behavior may be characteristic of a deep primate heritage that goes back millions of years."
Though ring-tailed lemurs spend more time on the ground and in the caves than most lemurs, they still need trees to survive. Deforestation in Madagascar has put them on the IUCN's endangered species list, according to esciencenews.com.
