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What is the difference between two-toed sloths and three-toed sloths?
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sloth
Juvenile three-toed sloth (Bradypus) climbing a tree branch.
Two-toed sloths (family Megalonychidae) and three-toed sloths (family Bradypodidae) are distinct groups of tree-dwelling mammals that differ in several key biological and physical characteristics:
- Classification and Anatomy: While three-toed sloths have eight or nine neck vertebraeâallowing them to turn their heads through a 270° arcâtwo-toed sloths have only six or seven. Additionally, three-toed sloths have three long, curved claws on all four feet, whereas two-toed sloths have two claws on their forelimbs and three on their hind limbs.12
- Size and Appearance: Two-toed sloths are generally larger, weighing up to 8 kg (17.6 pounds), while three-toed sloths typically weigh about 4 kg (8.8 pounds). Their fur also differs: the outer hairs of three-toed sloths are cracked transversely, while those of two-toed sloths feature longitudinal grooves that harbor algae.12
- Reproduction: Gestation periods vary significantly; three-toed sloths have a gestation of less than six months, while two-toed sloths have a gestation of almost 12 months.12
- Behavior: Three-toed sloths often sit in tree forks, whereas two-toed sloths spend almost all their time hanging horizontally.3