Zoology: Less than slothful


    Biol. Lett. doi:10.1098/rsbl.2008.0203 (2008)

    Wild brown-throated three-toed sloths (Bradypus variegatus; pictured) sleep for a mere nine to ten hours a day, much less than the 16 hours of shut-eye observed in captive sloths.

    Niels Rattenborg of the Max Planck Institute for Ornithology in Starnberg, Germany, and his colleagues made the discovery by fitting a miniature electroencephalogram (EEG), which measures electrical activity in the brain, to three adult female sloths in the tropical forest surrounding the Smithsonian Tropical Research Institute in Panama.

    The recordings are the first of their kind from any animal in the wild. The researchers suggest that, because they need to find their own food and keep a look out for predators, other wild creatures may also spend less time in slumber than has been assumed from studies of animals in captivity.

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    Zoology: Less than slothful. Nature 453, 430 (2008) doi:10.1038/453430c

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