---
title: "What the sources say about the Three-Toed Sloth | AnimalTracks.wiki"
description: "46 claims from the Three-Toed Sloth profile, each beside the words of the source that backs it."
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# What the sources say about the Three-Toed Sloth (*Bradypus tridactylus*)

> 46 claims from the Three-Toed Sloth profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Three-Toed Sloth](https://animaltracks.wiki/animals/three-toed-sloth/)

## Bradypus tridactylus. Animal Diversity Web, University of Michigan.

https://animaldiversity.org/accounts/Bradypus_tridactylus/

| The page says | The source says |
| :--- | :--- |
| Forest canopy of Venezuela, Guyana, Suriname, French Guiana and northern Brazil | The three-toed sloth lives high in the canopy of tropical rainforests |
| three-toed sloths in general grow 1.5 to 2.5 feet (46 to 76 cm) long | Bradypus tridactylus grows to a length of between 1.5 and 2.5 ft. (note: scoped to three-toed sloths in general because ADW's account uses the name genus-wide (its range runs from southern Central America to north-eastern Argentina); 1.5 ft = 46 cm, 2.5 ft = 76 cm) |
| Three-toed sloths live high in the rainforest canopy | The three-toed sloth lives high in the canopy of tropical rainforests |
| feed on the twigs, buds and leaves of Cecropia trees | It feeds exclusively on twigs, buds, and leaves of trees of the genus Cecropia. (note: 'exclusively' dropped: a 1999-era genus-wide claim) |
| Twigs, buds and leaves of Cecropia trees | It feeds exclusively on twigs, buds, and leaves of trees of the genus Cecropia. |
| They need relatively little food and run a lower metabolic rate than other mammals of similar size | needs relatively little food and has a lower rate of metabolism than do other mammals found about the same size |
| at night a sloth's body temperature drops to save energy | at night, a sloth's body temperature drops as much as 12 degrees in order to preserve energy (note: the 12-degree figure is cut: ADW gives no unit) |
| green algae living in the hair can give a sloth an overall greenish look that camouflages it in the canopy | Very small green algae sometimes live mutualistically in the pits of the hair, which gives the sloth an overall greenish appearance that camouflouges it in the forest canopy. |
| A metabolism slower than other mammals its size, and fur algae that can tint it green for canopy camouflage | has a lower rate of metabolism than do other mammals found about the same size |
| A metabolism slower than other mammals its size, and fur algae that can tint it green for canopy camouflage | gives the sloth an overall greenish appearance that camouflouges it in the forest canopy |
| It is usually a loner | The three-toed sloth is usually solitary. |
| Three-toed sloths defend themselves from predators like jaguars with long arms, sharp claws and sharp teeth | It also defends itself from predators like jaguars with its long arms, sharp claws, and sharp teeth. |
| On the rare occasions one comes down to the ground, it drags itself along by its hands. It can stand on its feet but cannot walk on them. In water, though, it is an excellent swimmer | During the rare times it drops to the ground, it moves by dragging itself by its hands. The sloth can stand on its feet, but cannot walk on them. Surprisingly though, the three-toed sloth is an excellent swimmer. |
| runs a lower metabolic rate than other mammals of similar size | needs relatively little food and has a lower rate of metabolism than do other mammals found about the same size (note: vibe.reason, re-paired in wave 121) |
| A slow-metabolism canopy dweller | needs relatively little food and has a lower rate of metabolism than do other mammals found about the same size (note: tagline; 'canopy' from ADW 'lives high in the canopy of tropical rainforests') |

## Bradypus tridactylus. AnAge: The Animal Ageing and Longevity Database.

https://genomics.senescence.info/species/entry.php?species=Bradypus_tridactylus

| The page says | The source says |
| :--- | :--- |
| Adults average about 4.25 kg | Adult weight 4,250 g (note: AnAge's 'Life history traits (averages)' table, species entry; replaces ADW's 2.25 to 5.5 kg, whose account gives a genus-wide range (southern Central America to north-eastern Argentina)) |
| No detailed study of its lifespan exists, but it has been estimated to live up to 40 years in the wild | There are no detailed studies of longevity in this species but it has been estimated they live up to 40 years in the wild |

## Pool et al. (2022). Bradypus tridactylus. The IUCN Red List of Threatened Species 2022: e.T3037A210442660.

https://doi.org/10.2305/iucn.uk.2022-2.rlts.t3037a210442660.en

| The page says | The source says |
| :--- | :--- |
| is found in the forests of Venezuela, Guyana, Suriname, French Guiana and northern Brazil | Brazil (Amazonas, Amapá, Roraima, Pará); French Guiana; Guyana; Suriname; Venezuela, Bolivarian Republic of (Venezuela (mainland)) (note: native range from the 2022 assessment page, read by hand in Chrome; 'forests' from its HABITAT AND ECOLOGY line; the four Brazilian states are all northern Brazil) |
| is found in the forests of Venezuela, Guyana, Suriname, French Guiana and northern Brazil | HABITAT AND ECOLOGY Forest |
| Forest canopy of Venezuela, Guyana, Suriname, French Guiana and northern Brazil | Brazil (Amazonas, Amapá, Roraima, Pará); French Guiana; Guyana; Suriname; Venezuela, Bolivarian Republic of (Venezuela (mainland)) |
| The Red List rated it Least Concern in 2022 | Bradypus tridactylus has most recently been assessed for The IUCN Red List of Threatened Species in 2022. Bradypus tridactylus is listed as Least Concern. |
| though its population is decreasing | POPULATION TREND Decreasing |
| Least Concern | IUCN Red List category: Least Concern (LC). (note: GBIF's copy of the 2022 Red List assessment; category only, per the source pack) |

## De Moura Filho, Huggins & Lines (1983). Sleep and waking in the three-toed sloth, Bradypus tridactylus. Comparative Biochemistry and Physiology Part A: Physiology.

https://doi.org/10.1016/0300-9629(83)90336-5

| The page says | The source says |
| :--- | :--- |
| In a lab study that combined direct observation with brain recordings, pale-throated three-toed sloths spent about 70 percent of their time asleep | The sleep-waking cycles of the three-toed sloth, Bradypus tridactylus, were studied by direct observation and polygraphic recording and the results were correlated. ... Animals spent about 30% of the time in various degrees of waking behavior and about 70% asleep. (note: lab setting from 'in the laboratory situation animals were sleeping most soundly between 6 a.m. and noon') |
| Their sleep came in several bouts, and the recordings split it into light, deep and paradoxical sleep | EEG patterns of sleep were divided into five types: two in light sleep, two in deep sleep and one in paradoxical sleep. ... The pattern of sleep is polycyclic (note: polycyclic = several sleep bouts a day) |
| spent about 70 percent of its time asleep in a lab study | Animals spent about 30% of the time in various degrees of waking behavior and about 70% asleep. (note: vibe.reason; lab setting from 'in the laboratory situation') |

## Taube et al. (1999). Distribution of Two Sympatric Species of Sloths (Choloepus didactylus and Bradypus tridactylus) along the Sinnamary River, French Guiana. Biotropica.

https://doi.org/10.1111/j.1744-7429.1999.tb00418.x

| The page says | The source says |
| :--- | :--- |
| during a wildlife rescue along French Guiana's Sinnamary River, over 73 percent of the pale-throated sloths captured were solitary | In both species, over 73 percent of individuals captured were solitary |
| during a wildlife rescue along French Guiana's Sinnamary River | During the filling of the Petit Saut dam in French Guiana, a wildlife rescue operation was conducted for 17 months. |

## Taube et al. (2001). Reproductive biology and postnatal development in sloths, Bradypus and Choloepus: review with original data from the field (French Guiana) and from captivity. Mammal Review.

https://doi.org/10.1111/j.1365-2907.2001.00085.x

| The page says | The source says |
| :--- | :--- |
| pale-throated three-toed sloth pregnancies seem to last about six months, with roughly 12 months between one birth and the next, and a young sloth becomes independent from its mother at about five months old | In Bradypus tridactylus pregnancy seems to last 6 months, the inter‐birth interval is approximately 12 months, and the age at which young become independent is about 5 months. |

## Darienko & Pröschold (2024). Prasiolopsis wulf-kochii (Prasiolales, Trebouxiophyceae), a New Species Occurring in Hairs of the Sloth Bradypus tridactylus. Plants.

https://doi.org/10.3390/plants13172405

| The page says | The source says |
| :--- | :--- |
| In 1977, Wulf Koch, curator of an algae collection at Germany's University of Göttingen, isolated one of those algae from the hairs of a pale-throated sloth in Brazil's Amazon | The species is named in honor of Dr. Wulf Koch who was the curator of the Culture Collection of Algae (SAG) at the University of Göttingen (1954–1979). He isolated this strain in 1977 from the hairs of the sloth Bradypus tridactylus. |
| isolated one of those algae from the hairs of a pale-throated sloth in Brazil's Amazon. It was filed under the name Trichophilus welckeri | SAG 84.81: Brazil, Amazonia, from hairs of the sloth Bradypus tridactylus ; assigned as Trichophilus welckeri . |
| In 2024, scientists re-examined its shape and DNA and found it belonged in a different genus | Our investigations clearly showed that this strain differed in morphology, especially of the chloroplast, from those originally described for Trichophilus (note: 2024 is the paper's year; 'DNA' is the SSU and ITS rDNA phylogeny in the next sentence) |
| They described it as a new species and named it Prasiolopsis wulf-kochii, after him | this strain represented a new species of Prasiolopsis, which we proposed here as P. wulf-kochii |
| They described it as a new species and named it Prasiolopsis wulf-kochii, after him | The species is named in honor of Dr. Wulf Koch |

## Monge Nájera (2021). Why sloths defecate on the ground: rejection of the mutualistic model. UNED Research Journal.

https://doi.org/10.22458/urj.v13i1.3438

| The page says | The source says |
| :--- | :--- |
| Sloths carry a complex community of organisms in their hair, including moths and algae | Sloths are arboreal mammals that harbor a complex community of organisms in their fur, including moths and algae |
| whose fur hosts its own community of moths and algae | Sloths are arboreal mammals that harbor a complex community of organisms in their fur, including moths and algae |
| Climbing down to defecate on the ground puts a sloth at risk from predators, and scientists have proposed at least five explanations for why sloths do it | Some sloths descend to defecate and urinate on the ground, increasing the risk of predation by ground animals. At least, five hypotheses have been proposed to explain this behavior |
| One is a partnership with fur moths: the sloth covers its droppings to benefit moth larvae that develop inside them | This model proposes that sloths defecate on the ground, and cover their feces to benefit moth larvae; these larvae develop inside fecal pellets in the |
| That model was built on the brown-throated three-toed sloth (Bradypus variegatus) | The current version of the mutualistic model states that sloths of the species B. variegatus lick and digest algae from their hair to obtain nutrients |
| a 2021 review found it contradicted by the scientific literature | The mutualistic model is contradicted by the scientific literature (note: 2021 is the paper's year (UNED Research Journal 13(1), June 2021)) |
| The pale-throated sloth may not even follow the same script | Maybe we should pay more attention to B. tridactylus, which sometimes defecates from the canopy |
| Bradypus tridactylus sometimes relieves itself straight from the canopy, and the review's author suggests it may be on its way to a more fully tree-bound life | Maybe we should pay more attention to B. tridactylus, which sometimes defecates from the canopy (Waage & Best, 1985; Hayssen, 2009), and may be in the process of evolving a more fully arboreal life. |
| Business from the branches | sometimes defecates from the canopy |

## Barros, Sampaio & Schneider (2003). Phylogenetic analysis of 16S mitochondrial DNA data in sloths and anteaters. Genetics and Molecular Biology.

https://doi.org/10.1590/s1415-47572003000100002

| The page says | The source says |
| :--- | :--- |
| a close relative | the split between Bradypus torquatus and the proto-Bradypus tridactylus / B. variegatus was estimated as about 7.7 million years ago (MYA) |
| The maned sloth's lineage is estimated to have split off from the shared ancestor of the pale-throated and brown-throated three-toed sloths around 7.7 million years ago. | the split between Bradypus torquatus and the proto-Bradypus tridactylus / B. variegatus was estimated as about 7.7 million years ago (MYA) |
| A mitochondrial DNA study suggests it is more closely related to the brown-throated sloth than to the maned sloth. | the split between Bradypus torquatus and the proto-Bradypus tridactylus / B. variegatus was estimated as about 7.7 million years ago (MYA) (note: the paper groups tridactylus and variegatus as a single 'proto' lineage that torquatus (the maned sloth) split from first, implying tridactylus and variegatus share a more recent common ancestor with each other than either does with torquatus) |