THE ANIMAL FILES

Linnaeus's two-toed sloth

Choloepus didactylus

“Two-toed” names the forefeet, not every foot on the animal.

Linnaeus’s two-toed sloth is a nocturnal, tree-dwelling mammal of South American rainforests. Long fur can carry algae, and its leaf-focused diet is processed slowly. Its teeth are also unusual: they lack enamel and keep growing.[1]

Follow the evidence ↓
Linnaeus's two-toed sloth
Image: Dave Pape · Commons · Public domain
Lifestyle
Mostly solitary, nocturnal and arboreal[1]
Teeth
Ever-growing dentine without enamel[1]
Coat
Algae can give wild fur a greenish hue[1]

Fur with an unusual direction

Belly hair parts along the midline and runs toward the back, opposite to the usual pattern in many mammals. During wet conditions, algae growing on the fur can add a greenish tint. This is growth on the coat, not a claim that the mammal produces green pigment itself. Young animals tend to have softer, darker fur.[1]

Teeth without the usual surface

The species lacks incisors and has relatively few teeth. Those teeth are rootless, contain layers of dentine and grow continuously without enamel. “Toothless” is therefore an inaccurate literal description of this sloth, even though historical names for its larger group have sometimes encouraged that misunderstanding.[1]

Canopy routes and slow processing

Rainforest vines provide routes between trees. Leaves dominate the described diet, although its full range of foods is incompletely known. A low metabolism and large digestive system are associated with long retention of food. The animal can also swim across waterways; moving slowly in branches does not mean complete inability to cross a river.[1]

A COMMON MIX-UP

Does a sloth have no teeth at all?

No. This species has teeth, but they lack enamel and incisors are absent.[1]

TRY A LITTLE REASONING

Why is a greenish coat not enough to conclude an animal makes green pigment?

Reveal the explanation

In this sloth, algae growing on the fur can supply that colour; the colour source is an organism on the coat.[1]

Sources & editorial notes

Adapted and translated from the cited Wikipedia revisions, with source-linked reasoning. Image credit and licence are listed separately above.

Adapted and translated from Wikipedia contributors; exact revisions are linked below. CC BY-SA 4.0

  1. Wikipedia contributors — Choloepus didactylus (adapted and translated; exact revision)
  2. NCBI Taxonomy — Choloepus didactylus (identity and game lineage)

Last fact check:

One discovery leads to another

Common silky anteaterA small forest anteater whose old name once covered several species.Cyclopes didactylus ↗European hedgehogA spiny visitor with more than one kind of nest.Erinaceus europaeus ↗European moleTiny, fur-hidden eyes are still eyes that can detect light.Talpa europaea ↗