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."

News
A model of a Neanderthal man on display at the National Museum of Prehistory in Dordogne, France
science
News
Richard Dawkins dedicated his book 'The Greatest Show on Earth' to Josh Timonen
newsThat's Richard Dawkins on babies with Down Syndrome
Arts and Entertainment
Eye of the beholder? 'Concrete lasagne' Preston bus station
architectureWhich monstrosities should be nominated for the Dead Prize?
Extras
indybest
PROMOTED VIDEO
News
ebooksAn evocation of the conflict through the eyes of those who lived through it
Travel
Dinosaurs Unleashed at the Eden Project
travel
Arts and Entertainment
music
Sport
football
Life and Style
This month marks the 20th anniversary of the first online sale
techDespite a host of other online auction sites and fierce competition from Amazon, eBay is still the most popular e-commerce site in the UK
News
i100
Independent
Travel Shop
the manor
Up to 70% off luxury travel
on city breaks Find out more
santorini
Up to 70% off luxury travel
on chic beach resorts Find out more
sardina foodie
Up to 70% off luxury travel
on country retreats Find out more
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

Quantitative Analyst (Financial Services, Graduate, SQL, VBA)

£45000 per annum: Harrington Starr: Quantitative Analyst (Financial Services, ...

Application Support Engineer (C++, .NET, VB, Perl, Bash, SQL)

Negotiable: Harrington Starr: Application Support Engineer (C++, .NET, VB, Per...

C# .NET Software Developer (Client-Side, SQL, VB6, WinForms)

Negotiable: Harrington Starr: C# .NET Software Developer (Client-Side, SQL, VB...

C# Developer (Genetic Algorithms, .NET 4.5, TDD, SQL, AI)

£40000 - £60000 per annum + Benefits + Bonus: Harrington Starr: C# Developer (...

Day In a Page

Middle East crisis: We know all too much about the cruelty of Isis – but all too little about who they are

We know all too much about the cruelty of Isis – but all too little about who they are

Now Obama has seen the next US reporter to be threatened with beheading, will he blink, asks Robert Fisk
Neanderthals lived alongside humans for centuries, latest study shows

Final resting place of our Neanderthal neighbours revealed

Bones dated to 40,000 years ago show species may have died out in Belgium species co-existed
Scottish independence: The new Scots who hold fate of the UK in their hands

The new Scots who hold fate of the UK in their hands

Scotland’s immigrants are as passionate about the future of their adopted nation as anyone else
Britain's ugliest buildings: Which monstrosities should be nominated for the Dead Prize?

Blight club: Britain's ugliest buildings

Following the architect Cameron Sinclair's introduction of the Dead Prize, an award for ugly buildings, John Rentoul reflects on some of the biggest blots on the UK landscape
eBay's enduring appeal: Online auction site is still the UK's most popular e-commerce retailer

eBay's enduring appeal

The online auction site is still the UK's most popular e-commerce site
Culture Minister Ed Vaizey: ‘lack of ethnic minority and black faces on TV is weird’

'Lack of ethnic minority and black faces on TV is weird'

Culture Minister Ed Vaizey calls for immediate action to address the problem
Artist Olafur Eliasson's latest large-scale works are inspired by the paintings of JMW Turner

Magic circles: Artist Olafur Eliasson

Eliasson's works will go alongside a new exhibition of JMW Turner at Tate Britain. He tells Jay Merrick why the paintings of his hero are ripe for reinvention
Josephine Dickinson: 'A cochlear implant helped me to discover a new world of sound'

Josephine Dickinson: 'How I discovered a new world of sound'

After going deaf as a child, musician and poet Josephine Dickinson made do with a hearing aid for five decades. Then she had a cochlear implant - and everything changed
Greggs Google fail: Was the bakery's response to its logo mishap a stroke of marketing genius?

Greggs gives lesson in crisis management

After a mishap with their logo, high street staple Greggs went viral this week. But, as Simon Usborne discovers, their social media response was anything but half baked
Matthew McConaughey has been singing the praises of bumbags (shame he doesn't know how to wear one)

Matthew McConaughey sings the praises of bumbags

Shame he doesn't know how to wear one. Harriet Walker explains the dos and don'ts of fanny packs
7 best quadcopters and drones

Flying fun: 7 best quadcopters and drones

From state of the art devices with stabilised cameras to mini gadgets that can soar around the home, we take some flying objects for a spin
Joey Barton: ‘I’ve been guilty of getting a bit irate’

Joey Barton: ‘I’ve been guilty of getting a bit irate’

The midfielder returned to the Premier League after two years last weekend. The controversial character had much to discuss after his first game back
Andy Murray: I quit while I’m ahead too often

Andy Murray: I quit while I’m ahead too often

British No 1 knows his consistency as well as his fitness needs working on as he prepares for the US Open after a ‘very, very up and down’ year
Ferguson: In the heartlands of America, a descent into madness

A descent into madness in America's heartlands

David Usborne arrived in Ferguson, Missouri to be greeted by a scene more redolent of Gaza and Afghanistan
BBC’s filming of raid at Sir Cliff’s home ‘may be result of corruption’

BBC faces corruption allegation over its Sir Cliff police raid coverage

Reporter’s relationship with police under scrutiny as DG is summoned by MPs to explain extensive live broadcast of swoop on singer’s home