The owl monkey: the slightly dazed look is telling. These nocturnal monkeys enjoy a long lie in, sleeping for 17 hours out of every 24.
The lion: regarded by many as royally beautiful, this king of the jungle needs his beauty sleep. Male lions slumber between 18 and 20 hours a day.
The opposum: these wingless marsupials are famed for the agility of their flight. But soaring through the air to get from tree to tree must take its toll on energy supplies. They doze for between 18 and 20 hours daily.
The armadillo: perhaps it is the weight of their armor that leads these skilled diggers to spend between 18 and 19 hours a day with their eyes firmly shut.
The brown bat: most common to North America, these bats hunt for a concentrated period at night, and spend an average of 19.9 hours tucked up in the comfort of their own wings.
The sloth: derived from the word “slow”, sloth has become synonymous with sleep. But it is not entirely fair. Although when in captivity, these creatures can snooze for up to 20 hours a day, recent research suggests they are twice as active in the wild.
The Koala: these tree-huggers laze about in a state of slumber for a whopping 22 hours a day. But it only seems to make them cuter.