View source for Linnaeus's two-toed sloth

{{Short description|Species of mammals related to anteaters and armadillos}}
{{Speciesbox
| name = Linnaeus's two-toed sloth<ref name=msw3>{{MSW3 Pilosa|pages=101|id=11800018}}</ref>
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 19 November 2021">{{cite iucn |author=Chiarello, A. |author2=Plese, T. |date=2014 |title=''Choloepus didactylus'' |volume=2014 |page=e.T4777A47439542 |doi=10.2305/IUCN.UK.2014-1.RLTS.T4777A47439542.en |access-date=19 November 2021}}</ref>
| image = Cholepus didactylus - Flickr - Dick Culbert.jpg
| image_caption = At [[London Zoo]]
| taxon = Choloepus didactylus
| authority = ([[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]]) <ref>{{cite book|last=Linnæus|first=Carl|title=Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I|year=1758|publisher=Laurentius Salvius|location=Holmiæ|page=35|url=https://www.biodiversitylibrary.org/item/80764#page/45/mode/1up|edition=10th|accessdate=23 November 2012|language=la}}</ref>
| synonyms = ''Bradypus didactylus'' <small>Linnaeus, 1758</small>
| range_map = Linné's Two-toed Sloth area.png
| range_map_caption = Linnaeus's two-toed sloth range
}}

'''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]].<ref name=":4">{{Cite journal|title = A Southern Extension of the Geographic Distribution of the Two-Toed Sloth, Choloepus didactylus (Xenarthra, Megalonychidae)|journal = Edentata|volume = 7|date = 2006-05-01|issn = 1413-4411|pages = 7–9|doi = 10.1896/1413-4411.7.1.7|first1 = Cristiano Trapé|last1 = Trinca|first2 = Francesca Belem Lopes|last2 = Palmeira|first3 = José|last3 = de Sousa e Silva Júnior|doi-access =free }}</ref> It's the largest [[Neontology#Extant_taxa_versus_extinct_taxa|extant]] sloth species.<ref name=GBIF>{{Cite web |title=Choloepus didactylus (Linnaeus, 1758) |url=https://www.gbif.org/species/5219519 |access-date=2023-09-19 |website=www.gbif.org |language=en}}</ref>

== Description ==
Males and females are the same size, growing to lengths of approximately 53 to 89 cm (21 to 35 in), not including the length of the tail, and weigh approximately 4 to 11 kg (9 to 24 lb).<ref name=GBIF/> Their fur color ranges from a brownish yellow to a pale tone of brown, however, in the wild their fur sometimes has a green hue from algae that grows on their fur during the rainy season.<ref name=GBIF/> Their belly fur is slightly lighter in color than the body and they have no undercoat.<ref name=GBIF/> The belly hair is parted along the midline and flows towards the animals back (spine), the opposite direction that fur flows on most other mammals.<ref name=GBIF/> Young sloths tend to have softer and darker fur than adults.<ref name=GBIF/>

== Phylogeny ==
Sloths belong to the order [[Pilosa]], which also includes [[anteater]]s. They belong to the super order [[Xenarthra]], which includes the [[Cingulata]]. Xenarthra are edentate or toothless. They lack [[incisor]]s and have a large reduction in number of teeth with only four to five sets remaining including [[canine tooth|canines]].<ref name=":0">{{Cite web|title = NOTICE ON THE OCCURRENCE OF SUPERNUMERARY TEETH IN THE TWO-TOED SLOTHS Choloepus didactylus AND C. hoffmanni|url = http://www.redalyc.org/articulo.oa?id=45725085029|website = Mastozoología Neotropical|date = 2012-01-01|accessdate = 2015-11-20|first1 = Robert K.|last1 = McAfee|first2 = Virginia L.|last2 = Naples}}</ref>

Modern sloths are divided into two families based on the number of toes on their front feet, [[Choloepodidae]] and [[Bradypodidae]]. Linnaeus's two-toed sloth and [[Hoffmann's two-toed sloth]] (''[[Choloepus hoffmanni]]'') belong to the family Choloepodidae, which included extinct ground sloths.<ref name=":1">{{Cite journal|title = Mammalian Species Choloepus didactylus|last = Adam|first = Peter J.|date = December 1999|journal = American Society of Mammalogists}}</ref>

== Morphology ==
''Choloepus didactylus'' are larger than three-toed sloths. They have longer hair, bigger eyes, and their back and front legs are more equal in length.<ref>{{cite web|last=Stewart|first=Melissa|title=At the Zoo: Slow and Steady Sloths|url=http://nationalzoo.si.edu/Publications/ZooGoer/2004/6/sloths.cfm|work=Zoogoer|publisher=Smithsonian Institution|accessdate=23 November 2012|archive-url=https://web.archive.org/web/20110607205345/http://nationalzoo.si.edu/Publications/ZooGoer/2004/6/sloths.cfm|archive-date=7 June 2011|date=November–December 2004}}</ref> Their ears, hind feet and head are generally larger than Bradypodidae. They do however have a shorter tail.<ref name=":2">{{Cite journal|title = Body measurements on 40 species of mammals from French Guiana|journal = Journal of Zoology|date = 1999-04-01|issn = 1469-7998|pages = 419–428|volume = 247|issue = 4|doi = 10.1111/j.1469-7998.1999.tb01005.x|first1 = C.|last1 = Richard-Hansen|first2 = J.-C.|last2 = Vié|first3 = N.|last3 = Vidal|first4 = J.|last4 = Kéravec}}</ref> Their shoulder height, the height from the shoulder blade to the tips of the claw is longer than three-toed sloths, indicating longer arms.<ref name=":2" />

The species has relatively few teeth; it has four to five sets including [[canine tooth|canines]] and lacks [[incisor]]s. Molars are indistinguishable from premolars.<ref name=GBIF/> The teeth are rootless<ref name=GBIF/> and lack [[Tooth enamel|enamel]], consisting only of two layers ever-growing [[dentin]].<ref name=":0" /> Supernumerary teeth have occasionally been observed, but this has been reported in almost all mammalian orders.<ref name=":0" />

== Ecology ==
''C. didactylus'' is a solitary, [[nocturnality|nocturnal]] and [[arboreal locomotion|arboreal]] animal, found in [[rainforest]]s. The two-toed sloth falls prey to [[Felidae|wild cats]] such as the [[ocelot]] and [[jaguar]] as well as large birds of prey such as the [[Harpy Eagle|harpy]] and [[Crested Eagle|crested eagles]]. Predation mainly occurs when the sloth descends to the ground in order to defecate or change trees.<ref name=":1" /> Anacondas have also been known to hunt sloths.<ref name=":1" /> It is able to swim, making it possible to cross rivers and creeks, but maybe also making it more available to a predator like an anaconda.

Two-toed sloths live in ever-wet tropical rainforests that are hot and humid. They tend to live in areas where there is a lot of [[vine]] growth so they can easily travel from tree to tree in the canopies of the forests.<ref name=":1" /> They mainly eat leaves, but there is lacking data on the extent of their diet due to their nocturnal lifestyle and camouflage.<ref name=":1" />

''C. didactylus'', similar to other sloth species, have a low rate of metabolism, food intake, and defecation, despite their relatively large body mass and their high volumes of [[methane]] production. They retain their digested material for long periods of time, due to a combination of their low defecation rates and large digestive systems.<ref name=":3">{{Cite journal |last1=Vendl |first1=C. |last2=Frei |first2=S. |last3=Dittmann |first3=M. T. |last4=Furrer |first4=S. |last5=Osmann |first5=C. |last6=Ortmann |first6=S. |last7=Munn |first7=A. |last8=Kreuzer |first8=M. |last9=Clauss |first9=M. |date=June 2016 |title=Digestive physiology, metabolism and methane production of captive Linné's two-toed sloths ( Choloepus didactylus ) |journal=Journal of Animal Physiology and Animal Nutrition |language=en |volume=100 |issue=3 |pages=552–564 |doi=10.1111/jpn.12356|doi-access=free |pmid=26122705 }}</ref> This long digestion period appears to cause the sloths’ high volumes of methane production, more than most other, similar herbivores.<ref name=":3" /> These high methane levels may also be the result of high [[formate]] levels in their digested material.<ref>{{Cite journal |last1=Dill-McFarland |first1=Kimberly A. |last2=Weimer |first2=Paul J. |last3=Pauli |first3=Jonathan N. |last4=Peery |first4=M. Zachariah |last5=Suen |first5=Garret |date=May 2016 |title=Diet specialization selects for an unusual and simplified gut microbiota in two- and three-toed sloths: Gut microbiotas of two- and three-toed sloths |url=https://onlinelibrary.wiley.com/doi/10.1111/1462-2920.13022 |journal=Environmental Microbiology |language=en |volume=18 |issue=5 |pages=1391–1402 |doi=10.1111/1462-2920.13022|pmid=26271635 |url-access=subscription }}</ref>

==See also==
* {{Cite book | last1 = Emmons | first1 = Louise H. | last2 = Feer | first2 = François | author-link  = Louise H. Emmons | title = Neotropical rainforest mammals. A field guide | edition = 2nd | publisher = [[University of Chicago Press]] | date = 1997-09-02 | location = Chicago | pages = 45 | url = https://books.google.com/books?id=hzqQlALoybIC | isbn =978-0-226-20721-6 | oclc = 44179508}}

==References==
{{Reflist}}

== Gallery==
<gallery>
Image:Zweizehenfaultier.png|1883 painting
Image:Choloepus didactylus - Buffalo Zoo.jpg|''Choelopus didactylus'' at Buffalo Zoo
Image:Sloth & baby, caught on Amazon. Leticia, Colombia1969.jpg|Sloth & baby, caught at [[Leticia, Colombia|Leticia]], [[Colombia]]
</gallery>

{{Wikispecies|Choloepus didactylus}}
{{Commons|Choloepus didactylus}}

{{Pilosa}}

{{Taxonbar|from=Q752691}}

[[Category:Sloths]]
[[Category:Mammals of Brazil]]
[[Category:Mammals of Colombia]]
[[Category:Mammals of French Guiana]]
[[Category:Mammals of Guyana]]
[[Category:Mammals of Peru]]
[[Category:Mammals of Suriname]]
[[Category:Mammals of Venezuela]]
[[Category:Fauna of the Amazon]]
[[Category:Mammals described in 1758]]
[[Category:Taxa named by Carl Linnaeus]]