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
One Direction's Zayn Malik gazes at a bouquet of flowers in the 'Night Changes' music video
people
News
people
News
'Free the Nipple' film screening after party with We Are The XX, New York, America - 04 Feb 2014
news
Arts and Entertainment
Russell Tovey, Myanna Buring and Julian Rhind Tutt star in Banished
tvReview: The latest episode was a smidgen less depressing... but it’s hardly a bonza beach party
ebooks
ebooksA special investigation by Andy McSmith
  • Get to the point
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

Recruitment Genius: Sales Manager

£35000 - £45000 per annum: Recruitment Genius: This is a unique opportunity to...

Recruitment Genius: Trainee Manager - Production

Negotiable: Recruitment Genius: Trainee Managers are required to join the UK's...

Recruitment Genius: Telesales Manager

£25000 - £35000 per annum: Recruitment Genius: You will maximise the effective...

SThree: Trainee Recruitment Consultant

£20000 - £25000 per annum + uncapped commission : SThree: Hello! I know most ...

Day In a Page

The saffron censorship that governs India: Why national pride and religious sentiment trump freedom of expression

The saffron censorship that governs India

Zareer Masani reveals why national pride and religious sentiment trump freedom of expression
Prince Charles' 'black spider' letters to be published 'within weeks'

Prince Charles' 'black spider' letters to be published 'within weeks'

Supreme Court rules Dominic Grieve's ministerial veto was invalid
Distressed Zayn Malik fans are cutting themselves - how did fandom get so dark?

How did fandom get so dark?

Grief over Zayn Malik's exit from One Direction seemed amusing until stories of mass 'cutting' emerged. Experts tell Gillian Orr the distress is real, and the girls need support
The galaxy collisions that shed light on unseen parallel Universe

The cosmic collisions that have shed light on unseen parallel Universe

Dark matter study gives scientists insight into mystery of space
The Swedes are adding a gender-neutral pronoun to their dictionary

Swedes introduce gender-neutral pronoun

Why, asks Simon Usborne, must English still struggle awkwardly with the likes of 's/he' and 'they'?
Disney's mega money-making formula: 'Human' remakes of cartoon classics are part of a lucrative, long-term creative plan

Disney's mega money-making formula

'Human' remakes of cartoon classics are part of a lucrative, long-term creative plan
Easter 2015: 14 best decorations

14 best Easter decorations

Get into the Easter spirit with our pick of accessories, ornaments and tableware
Inside the Kansas greenhouses where Monsanto is 'playing God' with the future of the planet

The future of GM

The greenhouses where Monsanto 'plays God' with the future of the planet
Britain's mild winters could be numbered: why global warming is leaving UK chillier

Britain's mild winters could be numbered

Gulf Stream is slowing down faster than ever, scientists say
Government gives £250,000 to Independent appeal

Government gives £250,000 to Independent appeal

Donation brings total raised by Homeless Veterans campaign to at least £1.25m
Oh dear, the most borrowed book at Bank of England library doesn't inspire confidence

The most borrowed book at Bank of England library? Oh dear

The book's fifth edition is used for Edexcel exams
Cowslips vs honeysuckle: The hunt for the UK’s favourite wildflower

Cowslips vs honeysuckle

It's the hunt for UK’s favourite wildflower
Child abuse scandal: Did a botched blackmail attempt by South African intelligence help Cyril Smith escape justice?

Did a botched blackmail attempt help Cyril Smith escape justice?

A fresh twist reveals the Liberal MP was targeted by the notorious South African intelligence agency Boss
Tony Blair joins a strange and exclusive club of political leaders whose careers have been blighted by the Middle East

Blair has joined a strange and exclusive club

A new tomb has just gone up in the Middle East's graveyard of US and British political reputations, says Patrick Cockburn
Election 2015: Meet the top 12 wacky candidates seeking your vote in May

Election 2015

Meet the top 12 wacky candidates seeking your vote in May