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How many neck vertebrae do two-toed sloths have?

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A juvenile three-toed sloth hangs from a tree branch surrounded by green leaves in Costa Rica. — sloth Juvenile three-toed sloth (*Bradypus*) climbing a tree branch.

Two-toed sloths have six or seven neck vertebrae. While most mammals typically possess seven cervical vertebrae, sloths are notable exceptions to this rule.123