mammals living in the warm, humid tropical forests, sloths also have adaptations to stay warm! They are covered in dense hair-like fur.
This fur also serves as effective camouflage, because each individual hair contains a groove which holds blue-green algae.
Sloths are not social mammals, and indeed
seem to communicate very little with one another. Their main vocalizations are whistle-like sounds, but these are not often heard, perhaps
because sloths avoid any behavior that could attract attention to themselves.