I remember watching three-toed sloths in a forest in Panama some years ago. They were among the oddest but coolest animals I'd seen. "Sloth" comes from an old English word meaning slow, and these gentle tree-dwellers were almost a parody of super-slow-motion. They were cute as well and, like most everyone else, Pamelia and I are suckers for cute. (Remind me sometime to tell you the story of how we almost adopted the runt of a litter of baby goats.)
Tonight (Dec. 17) at 8 p.m., the Animal Planet channel is showing a documentary about a sloth sanctuary in Costa Rica (see video above). If you dare to watch it, you're likely to become a sloth fan. It's a pity that the very word sloth has come to mean laziness and apathy. Sloth is considered one of the deadly sins, if you believe in such things. Sloths surely don't, and in fact the sluggish pace of their movements and metabolism keep them alive. They stay safe by dwelling in trees, drawing little attention to themselves, and the plant matter they subsist on takes time to digest. I've read that two-thirds of a sloth's weight can be the leaves and buds sitting in its stomach. Today's meal may not make it all the way through a sloth's alimentary tract until next month. That helps explain why sloths need to relieve themselves only once a week.
On our trip to England in October we saw a skeleton of a giant sloth at the Natural History Museum in London. Giants sloths lived in South, Central and eventually the southwestern part of North America until they went extinct about 10,000 years ago. Any humans who might have seen one probably wouldn't have described it as cute. Giant sloths were as big as mammoths and had claws as long as your forearm. They weighed five tons.
Scientists haven't yet determined the full evolutionary history of sloths. Why, for example, are sloths one of the only two mammals (along with manatees) to have evolved with a different number of neck vertebra? (All other mammals, from humans to bats to whales, have seven; various types of sloths have between five and nine.) Mind you, pinning down every detail in sloths' 60-million-year evolutionary tale takes time. And, like sloths, scientists must be deliberate and careful in their work. Slow, even. Perhaps, in the best sense, slothful.
Today's Puzzlers
I haven't had time to include brainteasers in recent blog posts, but I hope to get them rolling again. Here are two that tap your memory and your knowledge:
1) List as many European countries as you can in five minutes. There are about 50.
2) List as many species of birds as you can in five minutes. There are about, uh, 10,000.