The etymology of the word “sloth” reveals roots pertaining to slow speed; but somehow the poor sloth garnered a reputation for being a constant committer of one of the seven deadly sins. In fact, sloths are slow — very slow — but not lazy. They simply are unable to move any faster. Sloths are cursed – or blessed, depending on your perspective – with a metabolism that is only 40 to 45 percent of what most animals of comparative size have. With so little to power their movement, it's no wonder that they can only climb 6 feet per minute.