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"