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What the sources say

Three-Toed SlothBradypus tridactylus

Every figure, record and mechanism on the Three-Toed Sloth profile was written from a source, and this is the working table behind it: 46 claims checked word for word against these sources. The left column is what the page says. The right column is the source's own words, copied, not paraphrased; a ... marks a cut and[brackets] an insertion. Open any source and check it yourself.

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Source
01

Animal Diversity Web, University of Michigan

Bradypus tridactylus. Animal Diversity Web, University of Michigan.

The page saysForest canopy of Venezuela, Guyana, Suriname, French Guiana and northern Brazil
The source saysThe three-toed sloth lives high in the canopy of tropical rainforests
The page saysthree-toed sloths in general grow 1.5 to 2.5 feet (46 to 76 cm) long
The source saysBradypus 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
The page saysThree-toed sloths live high in the rainforest canopy
The source saysThe three-toed sloth lives high in the canopy of tropical rainforests
The page saysfeed on the twigs, buds and leaves of Cecropia trees
The source saysIt feeds exclusively on twigs, buds, and leaves of trees of the genus Cecropia.Note: 'exclusively' dropped: a 1999-era genus-wide claim
The page saysTwigs, buds and leaves of Cecropia trees
The source saysIt feeds exclusively on twigs, buds, and leaves of trees of the genus Cecropia.
The page saysThey need relatively little food and run a lower metabolic rate than other mammals of similar size
The source saysneeds relatively little food and has a lower rate of metabolism than do other mammals found about the same size
The page saysat night a sloth's body temperature drops to save energy
The source saysat night, a sloth's body temperature drops as much as 12 degrees in order to preserve energyNote: the 12-degree figure is cut: ADW gives no unit
The page saysgreen algae living in the hair can give a sloth an overall greenish look that camouflages it in the canopy
The source saysVery 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.
The page saysA metabolism slower than other mammals its size, and fur algae that can tint it green for canopy camouflage
The source sayshas a lower rate of metabolism than do other mammals found about the same size
The page saysA metabolism slower than other mammals its size, and fur algae that can tint it green for canopy camouflage
The source saysgives the sloth an overall greenish appearance that camouflouges it in the forest canopy
The page saysIt is usually a loner
The source saysThe three-toed sloth is usually solitary.
The page saysThree-toed sloths defend themselves from predators like jaguars with long arms, sharp claws and sharp teeth
The source saysIt also defends itself from predators like jaguars with its long arms, sharp claws, and sharp teeth.
The page saysOn 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
The source saysDuring 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.
The page saysruns a lower metabolic rate than other mammals of similar size
The source saysneeds relatively little food and has a lower rate of metabolism than do other mammals found about the same sizeNote: vibe.reason, re-paired in wave 121
The page saysA slow-metabolism canopy dweller
The source saysneeds relatively little food and has a lower rate of metabolism than do other mammals found about the same sizeNote: tagline; 'canopy' from ADW 'lives high in the canopy of tropical rainforests'

Source
02

AnAge: The Animal Ageing and Longevity Database

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

The page saysAdults average about 4.25 kg
The source saysAdult weight 4,250 gNote: 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)
The page saysNo detailed study of its lifespan exists, but it has been estimated to live up to 40 years in the wild
The source saysThere are no detailed studies of longevity in this species but it has been estimated they live up to 40 years in the wild

Source
03

Pool et al. 2022

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

The page saysis found in the forests of Venezuela, Guyana, Suriname, French Guiana and northern Brazil
The source saysBrazil (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
The page saysis found in the forests of Venezuela, Guyana, Suriname, French Guiana and northern Brazil
The source saysHABITAT AND ECOLOGY Forest
The page saysForest canopy of Venezuela, Guyana, Suriname, French Guiana and northern Brazil
The source saysBrazil (Amazonas, Amapá, Roraima, Pará); French Guiana; Guyana; Suriname; Venezuela, Bolivarian Republic of (Venezuela (mainland))
The page saysThe Red List rated it Least Concern in 2022
The source saysBradypus tridactylus has most recently been assessed for The IUCN Red List of Threatened Species in 2022. Bradypus tridactylus is listed as Least Concern.
The page saysthough its population is decreasing
The source saysPOPULATION TREND Decreasing
The page saysLeast Concern
The source saysIUCN Red List category: Least Concern (LC).Note: GBIF's copy of the 2022 Red List assessment; category only, per the source pack

Source
04

De Moura Filho, Huggins & Lines 1983

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

The page saysIn a lab study that combined direct observation with brain recordings, pale-throated three-toed sloths spent about 70 percent of their time asleep
The source saysThe 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'
The page saysTheir sleep came in several bouts, and the recordings split it into light, deep and paradoxical sleep
The source saysEEG 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 polycyclicNote: polycyclic = several sleep bouts a day
The page saysspent about 70 percent of its time asleep in a lab study
The source saysAnimals 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'

Source
05

Taube et al. 1999

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

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

Source
06

Taube et al. 2001

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.

The page sayspale-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
The source saysIn 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.

Source
07

Darienko & Pröschold 2024

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

The page saysIn 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 source saysThe 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.
The page saysisolated one of those algae from the hairs of a pale-throated sloth in Brazil's Amazon. It was filed under the name Trichophilus welckeri
The source saysSAG 84.81: Brazil, Amazonia, from hairs of the sloth Bradypus tridactylus ; assigned as Trichophilus welckeri .
The page saysIn 2024, scientists re-examined its shape and DNA and found it belonged in a different genus
The source saysOur investigations clearly showed that this strain differed in morphology, especially of the chloroplast, from those originally described for TrichophilusNote: 2024 is the paper's year; 'DNA' is the SSU and ITS rDNA phylogeny in the next sentence
The page saysThey described it as a new species and named it Prasiolopsis wulf-kochii, after him
The source saysthis strain represented a new species of Prasiolopsis, which we proposed here as P. wulf-kochii
The page saysThey described it as a new species and named it Prasiolopsis wulf-kochii, after him
The source saysThe species is named in honor of Dr. Wulf Koch

Source
08

Monge Nájera 2021

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

The page saysSloths carry a complex community of organisms in their hair, including moths and algae
The source saysSloths are arboreal mammals that harbor a complex community of organisms in their fur, including moths and algae
The page sayswhose fur hosts its own community of moths and algae
The source saysSloths are arboreal mammals that harbor a complex community of organisms in their fur, including moths and algae
The page saysClimbing 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
The source saysSome 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
The page saysOne is a partnership with fur moths: the sloth covers its droppings to benefit moth larvae that develop inside them
The source saysThis model proposes that sloths defecate on the ground, and cover their feces to benefit moth larvae; these larvae develop inside fecal pellets in the
The page saysThat model was built on the brown-throated three-toed sloth (Bradypus variegatus)
The source saysThe current version of the mutualistic model states that sloths of the species B. variegatus lick and digest algae from their hair to obtain nutrients
The page saysa 2021 review found it contradicted by the scientific literature
The source saysThe mutualistic model is contradicted by the scientific literatureNote: 2021 is the paper's year (UNED Research Journal 13(1), June 2021)
The page saysThe pale-throated sloth may not even follow the same script
The source saysMaybe we should pay more attention to B. tridactylus, which sometimes defecates from the canopy
The page saysBradypus 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
The source saysMaybe 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.
The page saysBusiness from the branches
The source sayssometimes defecates from the canopy

Source
09

Barros, Sampaio & Schneider 2003

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

The page saysa close relative
The source saysthe split between Bradypus torquatus and the proto-Bradypus tridactylus / B. variegatus was estimated as about 7.7 million years ago (MYA)
The page saysThe 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 source saysthe split between Bradypus torquatus and the proto-Bradypus tridactylus / B. variegatus was estimated as about 7.7 million years ago (MYA)
The page saysA mitochondrial DNA study suggests it is more closely related to the brown-throated sloth than to the maned sloth.
The source saysthe 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

How the table was made: a writer drafted the profile from these sources and logged each claim with its quote, a reviewer with nothing but this table checked every sentence said no more than its quote, and a script confirmed each quote appears word for word in the source. The method is in the site'sAbout page.