Why The Sloth Can Hang Upside Down
Sloths are famous for being sluggish and spending the majority of their lives upside down. Sloths do not have the same problems as humans have of breathing upside down. This is because according to research their internal organs are fixed in place
Three toed sloths have their guts anchored to their lower ribs by special adhesions which prevent their organs from pressing down on their lungs.
The organs of a sloth can become quite heavy particularly when a lot of waste gets built up in their bowels. These remarkable animals reside in the rain forests of South and Central America and are so reluctant to use their energy that they leave the trees just once a week to poop. Sloths hold up to a third of their body weight in urine and feces by holding it in.
“For a mammal that spends a significant amount of time hanging upside down, this large abdominal weight pressing down on the lungs would make breathing very costly in terms of energy, if not impossible,” study author Rebecca Cliffe, a researcher from Swansea University who works at the Costa Rica Sloth Sanctuary, said in a statement.
Ms. Cliffe and her colleagues dissected two sloths and found adhesions that bear the weight of the stomach, bowels and liver when the animal is hanging upside down. The researchers reckon that the adhesions could cut the energy expenditure of a slot by between 7 to 13 per cent.
Ms. Cliffe says such savings are a big deal because the sloth only generates enough energy from its diet to move only when it is required and there is little energy left over for anything else. This means in terms of energy expenditure, it would be expensive if not impossible for a sloth to lift that additional weight with each breath without the adhesions.
The adhesions may also limit how flexible the sloth is in its body midsection, which is most probably why few other mammals have this feature. This internal binding however is well suited towards the sloth’s lifestyle because it enables them to hang upside down to reach food without using any additional energy and putting added pressure on their internal organs.