Sloths are species of mammals that are assigned to the taxonomic suborder or Folivora. They can be found in the rainforests of Central and South America, and are best known for being the slowest mammals in the world, which explains the meaning of its name as it refers to their slow movement. Modern sloths are classified into two different kinds of species according to the number of long claws they have on each foot; the two-toed sloths (Choloepus),and the three-toed sloths (Bradypus). Although the main distinction between the two-toed and the three-toed sloth relies heavily on the number of claws they have, it is sometimes misleading because both sloths have three-toes on their back legs.
Anatomy and Physiology
Sloths are characterized by their brown and slightly greenish fur coat, which grows to approximately 41 to 74cm long. Colonies of green algae, found within the sloth's fur, allow them to protect themselves from danger through camouflage. Sloths can also use the algae from their hair to for nutrients by licking it off themselves. The Sloth’s hair grows up toward the legs from their body, which is in the opposite direction than other mammals, because sloths spend a lot of time with their legs above their body. Other characteristics that identify the sloth are a flat head, short nose, big eyes, tiny ears, and long legs. Their legs measure roughly 20 to 27 centimeters and their average weight is about nine pounds. On each leg, sloths have a tough and curved claw (two for the two-toed sloth and three for the three-toed sloth) – their tough, huge, and hooked claws allow the Sloths to spend most of its time in trees. Some Sloths are known to have a short tail but there are also some that do not have a tail at all. Sloths have a slow metabolism so it takes longer for them to digest food which allows them to survive on a limited amount of food at a time. The body temperature of the sloth is closely related to the Sloth’s environment. For example, two-toed sloths' body temperature is around 24 to 33 Celsius degree, and weather and the time of day affect their body temperature. Also, three-toed sloths' body temperature ranges from 30 to 34 Celsius degree. Sloths move very slowly. Sloths walk on the ground at about 0.025 m/s–0.050 m/s. When they move from the branches, the speed is around 0.050 m/s - 0.083 m/s. While climbing, their moving speed is the fastest.
Sloths are mammals,so they reproduce sexually. They mate in the dry season of the rain forest. The slow movements of the Sloth sometimes get in the way of females finding mates. Normally, a female sloth will produce a baby every year but this may change depending on how slow the female sloth moves and find a mate. Their gestation period is about five to six months. They give birth upside down hanging in their trees. A newborn sloth is about 10cm long in height and weighs only about 340 grams.
Sloths can only live in limited place. They inhabit the rainforest of Central and South America. Sloths make their homes in trees and rarely go down to the ground. They touch ground only once a week to excrete their wastes. Sloths sleep around 18 hours per day in an upside down position. Sloths are omnivores. While they are awake, they eat food such as leaves from cecropia tree,fruits, insects, and flowers. Sloths are mainly preyed on by jaguars, harpy eagles, and humans. They can protect themselves by camouflage.
Ground Sloths are a group of extincted sloth. More than 80 genera of Ground Sloths are classified in multiple families by Paleontologist. Four species of Ground Sloths found in United States are Harlan's ground sloth (Glossotherium harlani). Jefferson's ground sloth (Megalonyx jeffersonii), Laurillard's ground sloth (Eremotherium laurillardi), and the Shasta ground sloth (Nothrotheriops shastensis). They became extinct approximately 10,000 years ago in North America. Ground Sloths are related to the modern sloths. The modern sloths stay at trees during most time; On the other hand, Ground Sloths spent much time on the ground. Also, Jefferson's and Haran's sloths were as big as oxen. They were herbivores, so their teeth were small and short.  In the United States, Ground Sloths became extinct for by two main reasons. The climate change occurred at the end of the Ice Age. Moreover, humans hunted Ground sloths and destroyed their habitats. 
Sloth is walking
Sloth is preyed for Harpy Eagle