Skip to Main Content
San Diego Zoo Wildlife Alliance logo
San Diego Zoo Wildlife Alliance Library logo

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

Two-toed Sloths (Choloepus spp.)

Activity Cycle

  • 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

Movements and dispersal

Home range

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

Social Behavior

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)



  • 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


  • 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

Agonistic Behavior and Defense


  • 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

Interspecies Interactions

  • 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

Nighttime Activity

Sloth climbing at night

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.

Page Citations

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

SDZWA Library Links