The two-toed sloth does everything while hanging upside down from trees, including eating, sleeping, mating and even giving birth!
Sloths move very slowly and sleep for up to 15 hours a day to conserve their energy.
This is mostly due to their diet, which consists of low-energy food such as leaves and occasionally fruit.
Sloths have grooved hair that allows algae to grow there, giving the animals a green tint that helps camouflage them in the forest.
If you spend a lot of time hanging in trees then you need to be able to hold tight, and the sloths have a very powerful grip. Their long claws curve around tree branches like a safety harness.
Despite this powerful grip, sloths actually have a relatively low muscle mass of around 25% - mammals usually have around twice as much.
Our pair of Two-toed Sloths arrived at Chester Zoo in February 2012 after moving from a zoo in Germany.
Tina, our female, and Camillo, the male, were both born in 2011.
Find the sloths on our map
Where they live: Central and South America
Habitat: Lowland and tropical forest
Size: 60 to 70cm
Conservation status: Least concern
Threats: Deforestation, hunted for meat and fur