Two-toed sloth

Sloths move very slowly and sleep for up to 15 hours a day to conserve their energy. This is mostly 
down to their diet, which is made up of low-energy food like leaves and fruit. Their food isn’t very nutritious and can take up to three weeks to digest, so they have multi-chambered stomachs to help aid this process. They also have enamel-less teeth which are adapted to cope with this tough diet. 

If you spend a lot of time hanging in trees then you need to be able to hold tight, so sloths have a very powerful grip as well as a curved spine which helps them live upside-down. Despite this powerful grip, sloths actually have a relatively low muscle mass of around 25% – mammals usually have around twice as much.