Answers to Last Issue's Do You Know?

Sloths have been made popular by Disney as the character Flash in the movie Zootopia. Here are some questions about them.

About Sloths
Different sloth groups can be easily identified by the number of long, curved claws on their forelimbs. The two-toed sloths, as the name suggests, have two claws on their front limbs, while the three-toed sloths have three claws on all four limbs. The two-toed sloths are also slightly larger than their three-toed counterparts, and both fall under different taxonomic Family. Altogether, there are six sloth species that are found in the Americas, mainly in the tropical rainforests of Central and South America. Sloths are so named because of their very low metabolism and deliberate movements. Sloth, related to slow, literally means "laziness".

1. Are sloths just slow in moving or is everything about them slow?
Ans: Everything about sloths is slow. They even digest food really slowly! Sloths are primarily folivores, that is, they eat leaves, fruits and sap of various trees.
Two-toed sloths are omnivorous, eating insects, fruits, and leaves.  Three-toed sloths, on the other hand, are almost entirely herbivorous (plant eaters); in addition, they eat the leaves of only a few trees. Leaves, their main food source, provide very little energy or nutrients, and do not digest easily, so sloths have large stomachs in which symbiotic bacteria break down the tough leaves. About two-thirds of a well-fed sloth's body weight consists of the contents of its stomach, and the digestive process can take a month or more to complete.

2. They use their claws to climb, but where do they spend a large part of their lives?
Ans: All sloths are tree-dwelling, spending most of their lives hanging motionless or slowly moving between tree branches using their long, curved claws. Everything from feeding, sleeping, resting to mating and giving birth happens in the trees. They sometimes remain hanging from branches even after death.
Sloths move only when necessary and even then, very slowly. They usually move at an average speed of 4 m per minute. Even if they are in danger from a predator they cannot move much faster than that.  On the ground, the maximum speed of sloths is 3 m per minute so they are only marginally faster on trees.
But there are times when even sloths must leave the comfort of their tree canopies and descend to the ground: Three-toed sloths go to the ground to urinate and defecate about once a week, digging a hole and covering it afterwards. They go to the same spot each time and so are vulnerable to predators. Considering the large energy expenditure and dangers involved in the journey to the ground and back up the tree, this behaviour has been described as a mystery.

2. Can sloths swim?
Ans: Sloths are surprisingly strong swimmers and can reach speeds of 13 m per minute, three times faster than on the ground. They use their long arms to paddle through the water and can cross rivers and swim between islands. Sloths can reduce their already slow metabolism even further and slow their heart rate to less than a third of normal, allowing them to hold their breath underwater for up to 40 minutes.
Life can be difficult on the ground for sloths since their long clawed arms and shorter, weak hind legs make it impossible to stand on all fours. Sloth species living near mangroves or rivers sometimes drop into water bodies and swim large distances (in a short amount of time) when searching for potential mating partners or seeking new territory.

3. What is special about their fur?
Ans: The sloth’s hair is home to many different organisms, from microbes, insects to fungi and algae. Sloths also have a special, symbiotic relationship with green algae for the purpose of supplementing their diet. In return, the green algae benefits from shelter and water since the sloth's fur is extremely good at absorbing and retaining water.
The algae-covered fur is also believed to work as a camouflage to avoid predation. Sloths are often hunted by predators such as harpy eagles, ocelots, and jaguars, who mainly rely on movement to track their prey. So, the algae-covered fur and motionless hanging, help sloths blend with their surroundings, making it almost impossible to detect them in the wild.
Recent research shows that some moths, which live in the sloth's fur, lay eggs in the sloth's feces. When they hatch, the larvae feed on the feces, and when mature, the moths fly up onto the sloth above. These moths may have a symbiotic relationship with sloths, as they live in the fur and promote growth of algae, which the sloths eat.

Sources
https://www.wwf.org.uk/learn/fascinating-facts/sloth;
ilovesloths_official instagram page;
Wikipedia