The Nose as the Center of the Universe

A sloth’s nose is it’s primary navigation system.  In a sea of tropical green, searching for tasty leaves with eyes is not going to be very productive.  Sloths are fairly short-sighted and do not have eyes that are developed for adjusting the lens to see distances.  A sloth can even retract its eyes into its eye sockets!  Sloth pupils usually stay small, even at night.

Instead, a sloth uses its nose.  The sloth basks, hanging easily from the trees, and immerses itself in a constant flow of scent wafting through the jungle.  It tests out every scent and heads off in the direction of the most delicious one…usually a tasty Cecropia tree.  Can you smell your way to your next dinner?

Sloth Facts: Anatomy for Being Upside-Down

While we all know that sloths are incredibly cute, there is still a lot to learn about sloths and how they live.

One thing that scientists discovered a few years ago is that sloths have special tissue adaptations so that they can easily maintain hanging upside-down without expending extra energy or putting pressure on their organs.

Imagine if you hung upside down all day long:  your lower organs would start pushing down on your lungs and diaphragm, which would make breathing harder and harder as the day went on.

Sloths have special tissue that anchors their liver and stomach to the lower ribs, and anchors the kidneys to the hip bones.  This helps make sure that the ribs are bearing the weight of the organs as they hang upside down.

By measuring lung capacity and breathing rates of sloths, the scientists estimated that having this tissue in place helps them conserve 7 - 13 percent more energy that they would otherwise expend simply breathing.  Since sloths are slow moving and take a long time to digest their food, this energy conservation is important.

More tissue stability likely makes the sloth less flexible.  But that’s OK because they go slow!

References:
National Geographic Blog: "To Breathe Upside-Down, Sloths Tape Organs To Their Ribs"

Sloth Scientist article by Becky Cliffe,  "SLOTH ORGANS HANG ON 'COAT HANGERS' FOR EASY UPSIDE-DOWN BREATHING"