Sloths are slow because of their herbivorous diet.
Sloths are notoriously slow. Living in rainforests in Central and South America, sloths spend most of their time hanging upside down in the trees, rarely coming down to the ground.
There are two main families of sloths, two-toed sloths, and three-toed sloths, and they all share something in common: They've been around for millions of years – 64 million, to be exact.
For comparison, modern humans have only been around for about 200,000 years.
Sloths slowness, as it turns out, is the key to their survival. Far from being lazy, sloths are actually really efficient at conserving energy, and it all has to do with their diet.
Spending most of their lives hanging upside in trees, sloths move no further than 125 feet per day. When they make it to the ground, they crawl at a pace of about 1 foot per minute, according to the World Wildlife Federation.
Their herbivorous diet is low in energy and lacks much of the nutrients needed — like fats and protein — for a balanced meal.
They also take days to digest a meal, meaning they only leave their perches to defecate around once a week, reports Scientific American.
Because sloths rarely move, they grow algae on their fur, helping them camouflage with their arboreal home. It's a neat trick for avoiding sharp-eyed eagles.
Beyond algae, sloth fur is also a habitat for a whole range of organisms, from moths and cockroaches to fungi.
While they mostly slumber on comfortable branches, here, this man's hand seems like a suitable substitute.
Sloths do most of their moving, and feeding, at night, snoozing away the hot temperatures of the day.
Deforestation throughout Central and South America is putting pressure on sloths. The pygmy sloth, the smallest of the sloths that only lives on an island of the Caribbean coast of Panama, is critically endangered.
When sloths leave the safety of their mother, they adopt part of their parent's home range, staying in touch through frequent calls, according to the WWF.
While sloths have strong bonds with their mothers, their low birth rate hurts their ability to recover from habitat destruction.
A sloth made his star turn in Planet Earth II, searching for love on the beautiful island of Escudo off the coast of Panama.