View full lesson: http://ed.ted.com/lessons/why-are-sloths-so-slow-kenny-coogan Sloths spend most of their time eating, resting, or sleeping; in fact, they descend from their treetops canopies...
========== In 1796, Thomas Jefferson received
a box of bones he couldn't identify. A long, sharp claw reminded him of a lion, but the arm bones
suggested a larger animal, one about three meters long. Thinking it might be huge unknown
species of North American lion, Jefferson warned explorers Lewis and Clark to keep an eye out
for this mysterious predator. But Jefferson's box of bones didn't
come from a lion. They came from an extinct giant sloth. Prehistoric ground sloths first appeared
around 35 million years ago. Dozens of species lived across
North, Central and South America, alongside other ancient creatures
like mastodons and giant armadillos. Some ground sloths, like the megalonychid,
were cat-sized, but many were massive. Jefferson's s...