The world's oldest recorded sloth in captivity, Miss C, has died at Adelaide Zoo.

Miss C was a Hoffmann's two-toed sloth, a species which moves so slowly algae grows on their furry coat, and she lived four times longer than expected.

At the ripe old age of 43 Miss C, who is believed to be Australia's last sloth, was sadly put down by her keepers on Friday after suffering from 'age-related health conditions', the zoo told Daily Mail Australia.

Adelaide Zoo Curator of Conservation and Native Fauna Dr Phil Ainsley said Miss C was found on Friday morning by her keepers looking visibly unwell.

Adelaide Zoo Curator of Conservation and Native Fauna Dr Phil Ainsley said Miss C (pictured) was found on Friday morning by her keepers looking visibly unwell

'The average life expectancy of a sloth in the wild is about 10-12 years old, so Miss C truly was a phenomenal creature and believed to be the oldest of her kind in the world,' Dr Phil said.

She was listed on an international database as the oldest sloth in captivity, confirmed Adelaide Zoo to Daily Mail Australia on Monday.

'The treatment Miss C required was very invasive and would likely only delay the inevitable so the hard decision was made to humanely euthanise her,' Dr Ainsley continued.

'The treatment Miss C required was very invasive and would likely only delay the inevitable so the hard decision was made to humanely euthanise her,' Dr Ainsley said (pictured is Adelaide Zoo)

'Although this is an extremely sad loss for us all it was the right thing to do for Miss C.'

Born at Adelaide Zoo in 1974, Miss C was an important part of Adelaide's Zoo's history and was dearly loved by staff, volunteers and visitors.

'We were extremely lucky to have called Miss C a member of our Adelaide Zoo family for so long,' Mr Ainsley said.

'Her long life is a true testament to the stellar care provided by our dedicated zoo staff over the years.

'Miss C will always hold a special place in the hearts of our zoo family and will be fondly remembered by all who travelled from near and far to visit our iconic friend,' Dr Ainsley continued

'Miss C will always hold a special place in the hearts of our zoo family and will be fondly remembered by all who travelled from near and far to visit our iconic friend.'

Sadly there are no other sloths left in Australia at this time and it could be 'awhile' before Adelaide Zoo can get another one, Dr Ainsley said.

The Hoffmann's two-toed sloth is a solitary, nocturnal and arboreal animal that inhabits parts of Central and South America including Honduras, Ecuador, Peru, Brazil and Bolivia.