Sloths are tree-dwelling mammals of the Neotropics, known for their remarkably slow movements. This pace is an adaptation to their low-calorie diet of leaves, resulting in a very low metabolic rate, the lowest recorded for any non-hibernating mammal of their size. They spend nearly their entire lives suspended upside down in the dense canopy, making them difficult to spot. Finding these animals requires understanding their biological differences, which dictate where they live in the tropical forests of Central and South America.
Identifying Sloth Species
There are six extant species of sloth, divided into two genera: the three-toed sloths (Bradypus) and the two-toed sloths (Choloepus). Although named for the digits on their forelimbs, all sloths have three claws on their rear limbs. The three-toed sloths include the Brown-throated, Pale-throated, Maned, and Pygmy species, while the two-toed group consists of Hoffmann’s and Linnaeus’s species.
These two groups differ in morphology, behavior, and diet. Three-toed sloths are smaller and are strict folivores, feeding almost exclusively on the leaves of select tree species. They are also more active during the day. Two-toed sloths are slightly larger, have a more uniform coat, and are omnivorous generalists, consuming leaves, fruits, and occasionally small insects. They tend to be more nocturnal.
A key biological distinction is the number of cervical vertebrae in the neck. Most mammals, including two-toed sloths, have seven cervical vertebrae, but the three-toed sloth possesses eight or nine. This extra flexibility allows the three-toed species to rotate its head up to 270 degrees. This helps it scan for predators without expending the energy required to move its entire body.
Geographic Distribution and Primary Habitats
Sloths are found in the Neotropical realm, spanning the rainforests of Central and South America. Their range extends from Honduras and Nicaragua down to countries like Colombia, Ecuador, Peru, Venezuela, Bolivia, and Brazil. They require a habitat with a warm, humid climate and a continuous, dense canopy to facilitate movement and provide shelter.
The Brown-throated three-toed sloth (Bradypus variegatus) is the most widespread species, thriving in various lowland tropical forests and ascending to elevations of 2,400 meters. Hoffmann’s two-toed sloth (Choloepus hoffmanni) also has a wide distribution across Central and South America, often sharing the same forest with a three-toed species.
Other species have restrictive ranges dictated by unique environmental conditions. The Maned three-toed sloth (Bradypus torquatus) is endemic to the Atlantic coastal forests of southeastern Brazil. The Pygmy three-toed sloth (Bradypus pygmaeus) is critically endangered and lives exclusively on Isla Escudo de Veraguas, a small island off the coast of Panama. Sloths live in the upper layers of the forest canopy, which offers protection from ground predators and access to their food source.
Viewing Sloths in the Wild and Captivity
Finding a sloth in the wild requires patience and often the assistance of an experienced local guide. Sloths’ greenish fur harbors symbiotic algae and insects, allowing them to blend into the humid forest environment. Their slow pace means they can be mistaken for a cluster of leaves or a termite nest, even when moving.
National parks and protected areas in Costa Rica, such as Manuel Antonio or Tortuguero, are known for healthy populations of the Brown-throated sloth. Observation requires binoculars and maintaining a distance of at least three meters (ten feet) to avoid causing stress. Avoid noisy behavior and the use of flash photography, which can disorient and frighten them.
For a reliable encounter, rescue centers and sanctuaries offer a chance to observe sloths up close. When choosing a facility, select one that enforces a strict no-contact policy. Hands-on interactions cause extreme stress to sloths and can normalize harmful wildlife exploitation. Ethical organizations focus on educational experiences and observation from a distance, supporting the welfare and conservation of the species.