The Walking Ecosystem - A Three-toed Sloth tree climbing in Costa Rica. It's shaggy coat has grooved hair that is host to symbiotic green algae which camouflages it in the trees and provides it nutrients. Because of the algae, sloth fur is a small ecosystem of its own, hosting many species of commensal and parasitic arthropods . The algae also nourishes sloth moths. They in turn are responsible for fertilizing algae on the sloth, which provides the sloth with nutrients.