What is a Sloth? Are They an Endangered Species?
What is a Sloth?
A sloth is a slow moving herbivorous mammal that has been around in the Americas for at least 60 million years. Until about 12,000 years ago, most of the many species were ground sloths, and some of them - most famously the Megatherium - were as large as elephants. At one time they inhabited both North and South America.
Today there are six living species of tree sloths in the rainforests of South America. Their closest relatives are armadillos and anteaters.
Modern sloths come in two varieties. Two species of two-toed sloths belong to family Megalonychidae, and four species of three-toed sloths are in family Bradypodidae. While the two types look similar and have similar ecological niches, evolutionarily they are not closely related. They range in size from two to three feet long, with the two-toed sloths somewhat larger and faster-moving than the three-toed sloths, and they live for 10-20 years. They are nocturnal animals that spend much of their day sleeping, hanging by their claws from tree limbs.
While their claws are large, sloths are herbivores, or plant eaters. They use the claws for protection rather than to kill food. The leaves they eat are hard to digest and low in nutritional value, and they have a very slow metabolism as a result. Sloths move very little and most of their movements are very slow, so as not to expend more energy than necessary.
Are Sloths Endangered?
While four of the sloth species range over large portions of northern South America and are common in protected areas with healthy habitat, two species of three-toed sloths, Bradypus torquatus (maned three-toed sloth) and Bradypus pygmaeus (pygmy three-toed sloth), are listed as endangered species on the IUCN Red List.
B. torquatus is found in small areas of tropical rainforest along the coast of eastern Brazil, where suitable habitat is quickly disappearing due to deforestation in favor of plantations, livestock pasture, and the production of lumber and coal. The species is also hunted for both food and sport.
B. pygmaeus is only found on one small island off the coast of Panama - and then it lives only in the mangrove forests surrounding the island, not on the island itself. Its habitat is threatened by tourism development, and visitors to the island sometimes hunt them.
What does endangerment mean for the rainforest?
While the prospect of sloth endangerment may not directly affect many around the world, their loss would be as unfortunate as any other extinction. Sloths have lived on Earth for thousands of years, but our rapid destruction of their habitat in the name of progress is upsetting the delicate balance of their ecosystem.
Sloths, in this way, serve as a benchmark for our stewardship of the Earth. If we are consciously planning our progress, we can protect the delicate habitats that these creatures call home. While they may not directly provide us with a service, they serve an important niche in the rainforest ecosystem and one change can quickly snowball into irreparable damage. We can learn from sloths an appreciation of slowness and take the time to plan our cities and agriculture with all creatures in mind.
Resources and Photo Credit
IUCN Red List of Threatened Species: Bradypus pygmaeus, Bradypus torquatus, Bradypus tridactylus, Bradypus variegatus, Choloepus didactylus, Choloepus hoffmanni
Animals of the Rainforest - Sloth - Caltech Space Radiation Lab
Ground Sloths - Illinois State Museum
Picture of two-toed sloth by Leyo and Stevenj, used under CC-A 2.5 license.