SLOTHS are only half as lazy as scientists believed – but they still manage nearly ten hours' sleep each day.
Although the mammal spends most of its time just hanging around, new brain-wave recordings show it does not get nearly as much shuteye as its image suggests.
When European explorers first discovered the creature in the canopy of trees of the tropi
cal rain forests of Central and South America they named it sloth after the Hebrew word "atsluwth", meaning idle.
Scientists believed a sloth may sleep for as much as 20 hours a day, but tiny EEG (electroencephalogram) recorders found that brown-throated three-toed sloths (Bradypus variegates) slumber for only 9.6 hours.
That is more than six hours less than previously reported in captivity and much less than commonly believed, said Dr Niels Rattenborg, of the Max Planck Institute for Ornithology in Starnberg, Germany.
Although the exact reason for the difference remains unclear, ecological demands may limit the time available for sleep in the wild.
Dr Rattenborg, whose findings are published in Biology Letters, said: "
Our results suggest that sleep in the wild may be markedly different from that in captivity. Sloths are particularly interesting because it is commonly believed they spend an inordinate amount of time sleeping.
"Indeed, in the only electrophysiological study of their sleep, sloths slept 15.85 hours a day in captivity. Interestingly, in contrast sloths in the wild just slept 9.63 hours."
Sloths are herbivores and feed on leaves, shoots, twigs and fruit. The three-toed sloth is the slowest mammal in the world. It takes a minute to travel two metres crawling along the ground.
The full article contains 282 words and appears in The Scotsman newspaper.
