Sloths are legally blind. These slow animals have rod monochromacy, a rare condition that means they lack cone cells in their eyes. Because of this sloths are colorblind, and can only see very poorly in dim lighting. Luckily, sloths incredible sense of smell more than makes up for this.
This extraordinary plant predator is half blind, half deaf and spends most of its time sleeping in trees. So how does a sloth's day compare to ours?
Sloths are blind. They have a very rare condition called rod monochromacy which means that they completely lack cone cells in their eyes. As a result all sloths are colour-blind, can only see poorly in dim light and are completely blind in bright daylight.
Sloths lost the ability to see very well early in their evolutionary history – before they split off from the anteaters approximately 64 million years ago!
The facial structure of a sloth gives the appearance that it is constantly smiling – even if it is experiencing pain, stress or anxiety.
A sloth does not search for leaves with its eyes. Its eyesight is very poor and it is short-sighted (Goffart 1971, pp. 106ff.; Mendel et al. 1985).
Having a good spatial memory is important for sloths as they have poor eyesight. They navigate around their home ranges using their memory and sense of smell! However, the sloths social skills and problem solving abilities are somewhat lacking, which often leads to them being labelled as “stupid”.
Sloths are blind in bright daylight. These slow animals have rod monochromacy, a rare condition that means they lack cone cells in their eyes. Because of this sloths are colorblind, and can only see very poorly in dim lighting. Luckily, sloths incredible sense of smell more than makes up for this.
Sloths are solitary creatures who want to be left alone, thus unlike household animals, they do not like to be touched. So, if you come too close for their comfort, they can be deadly and severely hurt people.
They can cause the sloth undue distress
There has been research done that shows that sloths definitely do not like being held. When they are held, their heart rates increase and they are visibly more alert, indicating that being held by people can be very distressing and disorienting.
Sloths live in tropical forests in South and Central America, and they actually move so slowly that algae grows on their fur.
It's very hard to determine the gender of a sloth, as there is virtually no difference between males and females. In fact, it is so hard to tell their sex, it's actually quicker to send a fur sample off for DNA testing than it is for zoo keepers to try and work it out for themselves.
Modern sloths, however, are thought to have avoided the extinctions that wiped out their larger relatives because they ascended into the trees.
But the species became extinct some 10,000 years ago. Due to poor eyesight and hearing, sloths mainly rely on their sense of smell and touch to forage. Sloths do have color vision, which is generally absent in mammals.
They are wild animals, and they belong in the wild. There are six sub species of sloths in Central America and South America, all of which are threatened by deforestation and degradation of their habitat (tropical forests), and by illegal trafficking.
Though some states do not require permission to keep sloths as pets, others mandate that you obtain a special permit. Sloths have adapted to a specific environment. A considerable amount of money would have to be spent to be able to recreate a comfortable and appropriate environment for a pet sloth.
Three-toed sloths are some of the slowest and seemingly laziest creatures in the world. Instead of evolving to eat more, they evolved to do less.
Sloths are known reservoirs of the flagellate protozoan which causes leishmaniasis in humans, and may also carry trypanosomes and the protozoan Pneumocystis carinii.
In fact, more than half of all sloth deaths are due to predators killing them while travelling to and fro their low latrines.
What looks like an open wound or blood-stained fur, however, is in fact completely normal. It is a little known fact that all male three-fingered sloths develop this striking and totally unexpected feature called a 'speculum' at sexual maturity.
Naked mole rats are nearly deaf because their ears can't amplify sound. Naked mole rats have poor hearing because, unlike other mammals, they have abnormal outer hair cells that can't amplify sound. The animals could be used to model human deafness and help develop treatments.
In a Twitter Q&A in last year, Sir David confessed he'd love to be a sloth for a day. This half-blind, half-deaf, slow-moving creature endeared itself to the broadcaster during filming of BBC's Life of Mammals, with its relaxed eating technique and regular napping.
The facial structure of a sloth gives the appearance that they are constantly smiling – even if they're experiencing pain, stress, or anxiety. When sloths are used as a photo prop for wildlife selfies, tourists may accidentally confuse this feature for happiness or contentment.
Sloths only urinate and defecate once a week, said Schlott. “So when the floodgates open, it's a big production,” she said.