The Lifestyle of a Real Sloth

Oct. 4, 2006 — -- Spend five minutes -- it only feels like five hours -- with a sloth, and you'll understand how it got its name. But there's nothing sinful about its sluggish style.

"Sloth," also pronounced "sloath," is Middle English for "slow," which perfectly describes the pace of this laid-back little furry creature. It's the original tree-hugger, spending most of its solitary, leaf-eating life dangling upside down from branches in the rain forests of Central and South America.

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Animal educator Kathleen LaMattina regularly introduces children visiting New York's Bronx Zoo to 12-year-old Frankie -- short for Francine -- as she slowly swings along a coat rack. LaMattina says Frankie's mellow metabolism is the key to her species' survival. She's not a couch potato. It just takes her seven days to digest her food.

LaMattina says, "They climb from tree to tree, branch to branch, [and] they only come down once a week." That one time they come down is to get rid of all the food in their system. And that's only one activity that sloths are in no rush to complete. Another is mating.

"They do it very slowly," LaMattina says, "and they do it high up in the trees ... and they do it sort of upside down."

That's how sloths spend most of their lives. They negotiate branches with the curved claws at the end of their lengthy limbs. They're also good swimmers. But on land, sloths move as though they've been gorging on milkshakes for a month.

"They kind of drag themselves. They're kind of clumsy," LaMattina says.

Well, not all of them. Sid the Sloth, from the "Ice Age" movies, leaves his real-life counterparts in the dust. Sid did for his species what Poomba did for wart hogs in "The Lion King." He put them on kids' radar screens. Sid also serves as a reminder that sloths first appeared tens of millions of years ago, long before anyone thought to name them for a sin. Back then, they acted -- and looked -- distinctly, well, unslothful.

Paleomammalogist Ross MacPhee has studied the evolution of mammals. He points out some key characteristics of sloths through the fossils and skeletons of ancient sloth cousins at New York's American Museum of Natural History. He says, much like the saber-toothed cats, mammoths and mastodons of the time, sloths were very large beasts, sometimes reaching at least 12 feet tall and weighing several tons. And they walked on the ground -- relatively quickly.

"We don't think he was slow," MacPhee says. "They were more cowlike. Moving along, ambling along, finding what they needed to eat. But not this very, very slow movement that we associate with the living sloths."

Ancient, giant ground sloths roamed from Antarctica to northern Canada. Today their compact, cuddly cousins prefer the view from the trees, in a safe tropical haven that is, unfortunately, shrinking because of human development.

There are two varieties -- a two-toed sloth and a three-toed sloth. Both are also vulnerable, because they just can't scamper away from a moving vehicle.

Which is far more deadly than having the same name as a sin.

"I think it's perfectly reasonable to regard slothfulness as a moral failing," MacPhee adds. "To transfer it to these animals is a little bit unjust, because it's not that they're just lazy -- it's the way they are."

And maybe they have something to teach us. Back at the Bronx Zoo, Frankie, a two-toed sloth, weighs just 17 pounds. Her unhurried, inverted approach to life could let her live until at least 30. As one of the kids who met her observes, "It's like watching all the other animals live by hyperspeed. It's like you're having a longer life because you're going slower, not faster."

Or, as two British performers once put it in song, "How sweet to be a sloth."