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Linnaeus's two-toed sloth

Choloepus didactylus

Also known as Southern two-toed sloth, Linnaeus’s Two-toed Sloth, Linné's Two-toed Sloth, Linné’s Two-toed Sloth, Unau

Mammals › Two-toed sloths (Pilosa) › Choloepodidae (Two-toed sloths)

Two-toed sloths are nocturnal, arboreal leaf- and fruit-eaters with a very slow metabolism. They need warm, humid, climbable housing.

Pet trade

Experience: Expert / facility

Linnaeus's two-toed sloth — Photo: Julien Renoult, CC BY 4.0, via Wikimedia Commons

Photo: Julien Renoult, CC BY 4.0, via Wikimedia Commons

Weight9–18 lb

Lifespanabout 28 years in care

ActiveNight

Sleep~15 hours a day

Care guide

Housing

High humidity, tropical warmth and plenty of hanging branches; they move poorly on the ground.

Sources 74

Diet

Leaves, fruit, berries and twigs; digestion can take about a month and they defecate about once a week.

Sources 74

Show the group care guide for sloths

Group care guide

Sloths

Applies to most species in this group. Habitat: Neotropical rainforest canopy. Individual species can differ, so compare with the species numbers above and the linked sources.

Housing & setup

Warm (75–85 °F), humid enclosures with ropes and branches; they rarely come down.

Sources 74 138 139

Diet

Leafy greens, vegetables and leaf-eater biscuits; very slow digestion.

Sources 74 138 139

Health watch

Overheating, chilling and obesity.

Sources 74 138 139

Understanding the animal

In the wild

Researched for this exact species, not its family. Good care copies these conditions.¹²³

Where it lives	Tropical forest canopy in the Guianas and Amazon basin, extending from Venezuela south into Brazil and west into Ecuador and Peru. Spends most of its life suspended from branches.
Ground it lives on	Arboreal; descends infrequently to defecate or change trees.
Active	Primarily nocturnal, resting extensively during daylight.
Social life	Mostly solitary; females may sometimes occupy the same tree.
Wild diet	Leaves, small twigs, fruit and berries; obtains moisture from vegetation and dew.
Behavior to plan for	Moves and feeds while hanging beneath branches and is awkward on land, although it swims well. Can defend itself with claws and teeth.

What this means for care

Provide a continuous network of overhead supports for inverted movement.
Make browse accessible while hanging and maintain ground access for defecation.
Allow undisturbed daytime rest and individual feeding space.

Native climate (measured)

Warm-season highs	about 89°F (up to 90°F in the hottest sampled areas)
Cool-season lows	about 70°F (down to 68°F in the coldest sampled areas)
Average temperature	77–80°F across sampled records
Relative humidity	82–85% on average (driest month about 81%)
Rainfall	about 2725 mm a year

Measured at 129 wild occurrence records sampled against WorldClim 2.1 climate data (1970–2000 averages). Air conditions in the range are ecological context, not enclosure settings: microhabitats such as burrows, leaf litter or basking rocks can be cooler, warmer or more humid.

Profile

Researched for this exact species. Sources are listed under In the wild above.

History

Linnaeus's two-toed sloth is a South American member of the family Choloepodidae, one of the two modern sloth families distinguished by the number of toes on the front feet. Choloepodidae also included extinct ground sloths.

Keeper tips

Prioritize elevated, interconnected climbing structures because the species naturally stays high in the canopy.
Provide supports that allow use of its long limbs and curved claws.
Design the environment around arboreal rather than ground-level movement.
Account for the species' leaf-cropping adaptations when considering feeding behavior.

Behaviors reported

It is described as strictly arboreal and stays high in rainforest canopy.
Newborns cling to their mother's belly for about five weeks.

Unique adaptations

Four long limbs of approximately equal length end in two curved claws.
Grooves in individual hairs collect algae, producing a greenish tint that helps camouflage the animal.
Belly hair grows from the stomach toward the back, opposite the direction typical of most mammals.
Small, continuously growing molars are worn down by chewing.
Hardened lips compensate for the lack of sharp teeth by shearing and cropping leaves.

Remarkable facts

It is the largest living sloth species according to the supplied Wikipedia source.
Adults are reported at approximately 21 to 35 inches long and about 9 to 24 lb in the Wikipedia source.
Males and females are approximately the same size.
The species lacks incisors and has only a small number of remaining teeth.
Females reach sexual maturity at about three years, while males mature at about four to five years.
Females give birth to one offspring at a time according to the supplied Animal Diversity Web material.

From the sources

Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.

Overview	Linnaeus's two-toed sloth (Choloepus didactylus), also known as the southern two-toed sloth, unau, or Linne's two-toed sloth is a species of sloth from South America, found in Venezuela, Suriname, Guyana, French Guiana, Colombia, Ecuador, Peru, and Brazil north of the Amazon River. There is now evidence suggesting the species' range expands into Bolivia. It's the largest extant sloth species. — Wikipedia (community-edited)
Where it lives	Choloepus didactylus is strictly arboreal, staying high in the canopy of the tropical rain forests, and maintaining a range of about 10-acres. — Animal Diversity Web
Wild diet	Choloepus didactylus feed primarily on vegetation, including berries, leaves, small twigs, and fruits, cropping the leaves with their lips. — Animal Diversity Web
Behavior	Sloths move slowly and deliberately. — Animal Diversity Web
Reproduction	Females of this species of sloth reach sexual maturity at 3 years of age, males reach sexual maturity between 4 and 5. — Animal Diversity Web
Appearance and size	Two-toed sloths have been called the slowest animals on earth. — Animal Diversity Web
Conservation	Two-toed sloths are in serious danger of losing their habitat due to logging of rain forests. — Animal Diversity Web

Data and studies

The numbers

Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.

Lifespan in care

Reported28–40years

Animal Diversity Web 7428–40

Maximum recorded lifespan

Highest reported36.8years

AnAge 16236.8

Myhrvold et al. 16336.8

Longest recorded lifespan reported by each database; typical lifespans are usually shorter. The AnAge record comes from an animal in human care.

Typical adult weight

Average of sources13.8lb

AnAge 16213.8

Myhrvold et al. 16313.8

Average adult body mass in each database (FishBase gives the maximum recorded weight).

Litter size

Average of sources1young

AnAge 1621

Myhrvold et al. 1631

Average per litter or clutch.

Gestation

Average of sources276days

AnAge 162279

Myhrvold et al. 163274

Female maturity

Average of sources3.5years

AnAge 1623.5

Myhrvold et al. 1633.5

Veterinary & husbandry research

Natural Canine Distemper Virus Infection in Linnaeus's 2-Toed Sloths (Choloepus didactylus) Watson AM et al., Veterinary pathology 2020
Systemic Streptococcus agalactiae infection with meningo-ventriculitis in a Linnaeus's two-toed sloth (Choloepus didactylus) Yoshida K et al., The Journal of veterinary medical science 2022
Characterization of the ovarian cycle in the two-toed sloths (Choloepus didactylus): an innovative, reliable, and noninvasive method using fecal hormone analyses Troll S et al., Theriogenology 2013
Environmental enrichment for a mixed-species nocturnal mammal exhibit Clark FE et al., Zoo biology 2012

Peer-reviewed papers that mention this species alongside captivity, zoos, veterinary care or aquaculture. Some cover several species or mention it only in passing, so check the abstract. See all 21 on PubMed → 170

Federal legal snapshot

Some federal rules apply

CITES Appendix II. Appendix II: international trade needs CITES export permits. CITES doesn't restrict buying a captive-bred animal within the U.S.; keep your purchase records. 173 186
USDA Animal Welfare Act. Keeping a pet for yourself doesn't need a federal license. Dealers (including many breeders who sell wholesale or sight-unseen) and exhibitors (including encounters and paid programs) generally need a USDA license and inspections; some small-scale breeders and retail sellers are exempt. 184

State law decides most of it. Each state sets its own permits and bans for exotic, native, venomous and dangerous animals, and cities and counties can be stricter. Find your state agency →

Animal Welfare Act standards

Warm-blooded animals not covered elsewhere (Subpart F). Applies to USDA-licensed or registered dealers, exhibitors (including encounters and paid programs) and research facilities. Private pet owners are not covered. These are legal minimums, not best care; the species care on this page goes further.

Facilities must be structurally sound and strong enough for the species, with reliable power and water, protected food storage and proper waste disposal. §3.125
Indoors: temperature regulated to protect from extremes, adequate ventilation without drafts, and lighting suited to the species that protects animals from excessive light. §3.126
Outdoors: shade from overheating sun, shelter suited to the local climate, and drainage. Animals must be acclimated before facing climate extremes. §3.127
Outdoor facilities need a perimeter fence at least 8 ft high for potentially dangerous animals (large cats, bears, wolves, rhinoceros, elephants) and 6 ft for others, at least 3 ft from the enclosure, unless USDA approves otherwise. §3.127
Space must allow each animal to make normal postural and social adjustments with adequate freedom of movement. Poor condition, stress or abnormal behavior can show the space is inadequate. §3.128
Food must be wholesome, palatable and of enough quantity and nutritive value for the species, age and condition, fed at least once a day except during hibernation, normal fasts or veterinary treatment. §3.129
Water must be available as often as needed for health and comfort, in clean receptacles. §3.130
Animals sharing an enclosure must be compatible, and must not be housed near animals that interfere with their health or cause them discomfort. §3.133
There is no general enrichment rule for this subpart; enrichment requirements apply to primates, birds and (exercise) dogs. §3.128

Source: 9 CFR Part 3, current eCFR text (USDA APHIS Animal Care).

Kept in captivity?

Every species on this site needs evidence that people actually keep it. For this one:

Included in our hand-checked list of animals kept as pets, livestock or in zoos
AnAge has a longevity record from an animal in captivity
Covered by one of our in-depth care sheets

Sources for this sheet

Animal Diversity Web (University of Michigan): Choloepus didactylus Zoo, university or veterinaryUniversity-hosted species account, mostly wild biology.
AnAge: The Animal Ageing and Longevity Database (Human Ageing Genomic Resources) Peer-reviewed researchCurated, referenced longevity and life-history records for thousands of species; maximum lifespans are often from zoo animals.
Myhrvold et al. (2015). An amniote life-history database. Ecology 96: 3109 Peer-reviewed researchPeer-reviewed compilation of life-history data for over 21,000 birds, mammals and reptiles.
Species+ (UNEP-WCMC and the CITES Secretariat) Zoo, university or veterinaryThe official database of species listed under CITES.
USFWS International Affairs: CITES Zoo, university or veterinaryFederal agency that issues CITES permits.
9 CFR 2.1: Animal Welfare Act licensing (USDA) Zoo, university or veterinaryWho needs a USDA license to breed, sell or exhibit animals.
Merck Veterinary Manual: Management of zoo animals Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
Merck Veterinary Manual: Nutrition: exotic and zoo animals Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
GBIF Backbone Taxonomy (Global Biodiversity Information Facility) Peer-reviewed researchInternational scientific taxonomy used here for classification.
Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
PubMed (U.S. National Library of Medicine) Peer-reviewed researchIndex of peer-reviewed veterinary, zoo and husbandry research.