What is a very slow animal?

"The sloth is an arboreal (tree living) animal that moves very slowly. Because of this, its name has taken on the meaning of a slow, lazy person. However the sloth is not moving slowly because it is lazy. It lives in an area where eagles are the major predator. Eagles, like most predators, have very keen eye-sight and are particularly able to detect movement. When the sloth moves through the trees very slowly, it is hard to detect its presence. Thus, the sloth's slow speed is really an advantage against its major predator. "

Sorce: madsci.org