Two-toed Sloths (Choloepus spp.) Fact Sheet: Behavior & Ecology

• Slow moving, solitary, arboreal, herbivores
• Two-toed sloth is exclusively nocturnal (three-toed sloth is active day and night)
• Activity begins about one hour following sunset
• Active about 11 hours throughout night
• Activity ceases about 2 hours before dawn
• Average 7.6 hours of activity/day
  • 55% of time is spent in bouts of continuous activity lasting 2 or more hours
• Sleep 15 to 18 hours per day
• Approximately 6 hours each day are spent foraging
• Most two-toed sloths change to a different tree each night
• Does everything hanging upside down — eating, sleeping, mating and even giving birth!
• Basal metabolic rates lie between 40 and 60% of that expected from their mass

Home range

• Varies between 1.2 and 6.5 ha for C. didactylus (Taube, 1997)

Social groups

• Typically solitary; females occasionally feed in the same tree
• Young will stay with mother for nine to twelve months, depending on the species (Taube 2001)

Tactile

• Mutual grooming observed only during infant/mother relationship — mother vigorously licks head, face and ano-genital region for first few weeks of infant's life. Stimulates young to pass urine and feces. (Meritt 1985)
•  Self grooming/scratching with fore claws

Vocalization

• Generally silent; hiss in defense; low bleats in distress
• Sloth infants separated from their mothers will let out a loud bleat lasting 30-90 seconds
  • Distress call is low-pitched
  • Three-toed young's call is a rising whistle (Montgomery & Sunquist 1974)
• Sloth ear appears designed for low-frequency sounds (Ramprashad 1985)

Olfaction/scent marking

• Excellent sense of smell. Olfactory bulbs well-developed
• Males scent mark on tree branches from a gland near the anus

Aggression

• Charges suspected aggressor, pulls objects to mouth with forearm and bites — sharp teeth are like canines of carnivores
• Three-toed sloth is more docile
  • Their front teeth are not sharp so they don't bite defensively
  • They are often taken for pets because of mild disposition

• Preyed upon by harpy eagles, anacondas, jaguars, ocelots and humans; excellent camouflage and slow movement help them elude predators
• Several species of pyramid moths occasionally inhabit fur (far more common on Bradypus)
• Sloths are hosts for several mosquito-borne virus diseases: St. Louis encephalitis and Venezuelan encephalitis
• Sloths are unusual virus hosts—show no symptoms of many diseases although high amounts of virus can be found in their blood
• By defecating at the base of their host cecropia tree, the sloth provides the tree with fertilizer

• Slow and deliberate
• Agile in trees, with claws hooking onto branches
• Climbing speed estimated at 1.8 to 2.4 meters/ minute (6 to 8 feet/ minute or 480 feet/ hour ) under duress 274.3 meters/hour (900 feet/hour)
• Slower on the ground: 16.1 meters/hour (53 feet/hour)
• Physically incapable of truly walking. Drag themselves with claws and forelimbs for short distances, usually on the way from one tree to another.
• Excellent swimmers. May drop from a tree into a river and swim to shore.
• Range: can cover 38.1 meters (125 feet) of forest turf each day

A two-toed sloth climbs at night around the San Diego Zoo.

Sloths spend about 6 hours foraging per day.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

Gilmore (2008)
Meritt (1985)
Montgomery and Sunquist (1978)
Ramprashad (1985)
Sunquist and Montgomery (1973)