Why do sloths hang upside down?

Scientists have discovered how the lethargic tree-dwellers have evolved to spend most of their slow-paced life upside down

Sloths, the lazy creatures famed (and envied) for their slow-paced, laidback lifestyle manage to spend most of their time hanging upside down because their internal organs are quite literally fastened in place, scientists have discovered.

The lethargic creatures can take up to a month to digest a single leaf, sleep for at least 10 hours a day and can only climb at a leisurely maximum speed of eight feet per minute.

The tree-dwellers head to the forest floor to go to the toilet just once a week, leaving scientists pondering how they are able to breathe with the full weight of all that waste matter pressing on their lungs.

At any one time, a third of a sloth's bodyweight is taken up by stored urine and faeces, making their stomach and bowel contents extremely heavy.

But scientists at the University of Swansea have now deduced that after spending 90 per cent of their lives hanging upside down, sloths have evolved 'attachments' in the abdomen.

These attachments work by anchoring organs in place such as the liver, stomach and bowel and prevent them weighing down on the diaphragm.

The team's findings are published in the Royal Society journal Biology Letters.

Rebecca Cliffe, one of the University of Swansea scientists who conducted the research at the Costa Rica Sloth Sanctuary, said: “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.

"Sloths have solved this problem by anchoring their organs against the rib cage. They have multiple internal adhesions that bear the weight of the stomach and bowels when the sloth hangs inverted.

“They generate just about enough energy from their diet to move when and where required, but there is not much left in the tank afterwards.

"It would be energetically very expensive, if not completely impossible, for a sloth to lift this extra weight with each breath were it not for the adhesions. The presence of these simple adhesions therefore really is vital."

Co-author Professor Rory Wilson, also from the University of Swansea, said: "Nothing that sloths do is normal. They are quite the most extraordinary and 'off-the-wall' mammals I have ever come across and yet we know so very little about them."

Start your day with The Independent, sign up for daily news emails
News
people
News
A survey carried out by Sainsbury's Finance found 20% of new university students have never washed their own clothes, while 14% cannot even boil an egg
science...and the results are not as pointless as that sounds
News
politicsIs David Cameron trying to prove he's down with the kids?
News
Dominique Alderweireld, also known as Dodo de Saumure, is the owner of a string of brothels in Belgium
newsPhilip Sweeney gets the inside track on France's trial of the year
PROMOTED VIDEO
News
Cumberbatch was speaking on US television when he made the comment (Getty)
people
Life and Style
tech
Arts and Entertainment
Tom DeLonge, Travis Barker and Mark Hoppus of Blink-182 pictured in 2011.
musicBassist Mark Hoppus and drummer Travis Barker say Tom Delonge is 'disrespectful and ungrateful'
Sport
football
Arts and Entertainment
Olivia Colman and David Tennant star in 'Broadchurch'
tvBroadchurch series 2, episode 4, review - contains spoilers
Sport
cyclingDisgraced cycling star says people will soon forgive his actions
News
Britain's Prince Philip attends a Garden Party at Buckingham Palace in London
people
ebooks
ebooksA year of political gossip, levity and intrigue from the sharpest pen in Westminster
Arts and Entertainment
Ed Sheeran will play three sell-out gigs at Wembley Stadium in July
music
News
i100
News
Lena Dunham posing for an official portrait at Sundance 2015
people
Arts and Entertainment
Under the skin: Sarah Kane in May 1998
theatreThe story behind a new season of Sarah Kane plays
Arts and Entertainment
Preening: Johnny Depp in 'Mortdecai'
filmMortdecai becomes actor's fifth consecutive box office bomb
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Ashdown Group: Assistant Management Accountant - Part Qualified CIMA / ACCA

£30000 per annum + benefits: Ashdown Group: We are recruitment for an Assistan...

Recruitment Genius: Field Sales Executive - OTE £50,000

£45000 - £50000 per annum: Recruitment Genius: This leading provider of design...

Recruitment Genius: Logistics Analyst

£23000 - £28000 per annum: Recruitment Genius: Would you like to be a part of ...

Recruitment Genius: Technical Manager - R&D - Paint

£35000 - £45000 per annum: Recruitment Genius: This growing successful busines...

Day In a Page

Woman who was sent to three Nazi death camps describes how she escaped the gas chamber

Auschwitz liberation 70th anniversary

Woman sent to three Nazi death camps describes surviving gas chamber
DSK, Dodo the Pimp, and the Carlton Hotel

The inside track on France's trial of the year

Dominique Strauss-Kahn, Dodo the Pimp, and the Carlton Hotel:
As provocative now as they ever were

Sarah Kane season

Why her plays are as provocative now as when they were written
Murder of Japanese hostage has grim echoes of a killing in Iraq 11 years ago

Murder of Japanese hostage has grim echoes of another killing

Japanese mood was against what was seen as irresponsible trips to a vicious war zone
Syria crisis: Celebrities call on David Cameron to take more refugees as one young mother tells of torture by Assad regime

Celebrities call on David Cameron to take more Syrian refugees

One young mother tells of torture by Assad regime
The enemy within: People who hear voices in their heads are being encouraged to talk back – with promising results

The enemy within

People who hear voices in their heads are being encouraged to talk back
'In Auschwitz you got used to anything'

'In Auschwitz you got used to anything'

Survivors of the Nazi concentration camp remember its horror, 70 years on
Autumn/winter menswear 2015: The uniforms that make up modern life come to the fore

Autumn/winter menswear 2015

The uniforms that make up modern life come to the fore
'I'm gay, and plan to fight military homophobia'

'I'm gay, and plan to fight military homophobia'

Army general planning to come out
Iraq invasion 2003: The bloody warnings six wise men gave to Tony Blair as he prepared to launch poorly planned campaign

What the six wise men told Tony Blair

Months before the invasion of Iraq in 2003, experts sought to warn the PM about his plans. Here, four of them recall that day
25 years of The Independent on Sunday: The stories, the writers and the changes over the last quarter of a century

25 years of The Independent on Sunday

The stories, the writers and the changes over the last quarter of a century
Homeless Veterans appeal: 'Really caring is a dangerous emotion in this kind of work'

Homeless Veterans appeal

As head of The Soldiers' Charity, Martin Rutledge has to temper compassion with realism. He tells Chris Green how his Army career prepared him
Wu-Tang Clan and The Sexual Objects offer fans a chance to own the only copies of their latest albums

Smash hit go under the hammer

It's nice to pick up a new record once in a while, but the purchasers of two latest releases can go a step further - by buying the only copy
Geeks who rocked the world: Documentary looks back at origins of the computer-games industry

The geeks who rocked the world

A new documentary looks back at origins of the computer-games industry
Belle & Sebastian interview: Stuart Murdoch reveals how the band is taking a new direction

Belle & Sebastian is taking a new direction

Twenty years ago, Belle & Sebastian was a fey indie band from Glasgow. It still is – except today, as prime mover Stuart Murdoch admits, it has a global cult following, from Hollywood to South Korea