Brown-throated three-toed sloth in Manuel Antonio National Park, Costa Rica

Feeling lazy? Today's your day.

Isn't it odd that many of us don't have to work on Labour Day, but International Sloth Day is just another Monday? If you're moving slow today, that's just fine: You're outpacing today's homepage subject, which spends 90 percent of its time scarcely moving a muscle.

Sloths like this three-toed specimen move very little to conserve the scant energy gained from their leaves-only diet. They live their whole lives hanging around in trees from their hooked claws, only descending for bathroom breaks and an occasional swim. Sloths even sleep in a dangling position—often snoozing away 20 hours of the day. Jealous?