(hours spent sleeping per 24 hours)
1. Koala: 20-22
2. Sloth: 20
3. Brown bat: 19.9
4. Giant armadillo: 18.1
5. Python: 18
5. North American opossum: 18
7. Owl monkey: 17
8. Human infant: 16
9. Tiger: 15.8
9. Tree shrew: 15.8
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