Neuroscience For Kids

Sloths Not So Lazy
October 2, 2008

When you think of a sloth, you probably think of an animal that lies around and sleeps all day long. In captivity, sloths do seem to sleep much of the time, in fact, almost 16 hours each day. New research from U.S. and German scientists, however, shows that a sloth's lazy reputation may not be deserved.

The research team went into the tropical rainforest of Panama and captured three wild brown-throated three-toed sloths (Bradypus variegatus). Each animal was fitted with a recorder to measure brain and muscle activity and then released back into the forest.

The scientists found that the sloths spent an average of 14.37 hours awake and 9.63 hours asleep. So, sloths sleep about 6 hours less in the wild than they do in captivity.

Sloths may sleep less in the wild because they need to hunt for food (mostly leaves from forest trees) and be on the lookout for predators (jaguars and large birds and snakes).

References and further information:

• Rattenborg, N.C., Voirin, B., Vyssotski, A.L., Kays, R.W., Spoelstra, K., Kuemmeth, F., Heidrich, W. and Wikelski, M., Sleeping outside the box: electroencephalographic measures of sleep in sloths inhabiting a rainforest, Biol Lett., 4:402-405, 2008.
• Three-toed sloth
• Sleep - Neuroscience for Kids

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