# Which animals sleep the least?

> Giraffes sleep 1.9 hours a day, the least of any mammal in the dataset.

Canonical: https://karelbusta.dev/data/sleep/animals-that-sleep-the-least

| # | Species | Total sleep (h/day) | REM sleep | Body weight | Order | Diet |
| --- | --- | --- | --- | --- | --- | --- |
| 1 | Giraffe | 1.9 h/day | 0.4 | 899.995 | Artiodactyla | herbi |
| 2 | Pilot whale | 2.7 h/day | 0.1 | 800 | Cetacea | carni |
| 3 | Horse | 2.9 h/day | 0.6 | 521 | Perissodactyla | herbi |
| 4 | Roe deer | 3.0 h/day | – | 14.8 | Artiodactyla | herbi |
| 5 | Donkey | 3.1 h/day | 0.4 | 187 | Perissodactyla | herbi |
| 6 | African elephant | 3.3 h/day | – | 6654 | Proboscidea | herbi |
| 7 | Caspian seal | 3.5 h/day | 0.4 | 86 | Carnivora | carni |
| 8 | Sheep | 3.8 h/day | 0.6 | 55.5 | Artiodactyla | herbi |
| 9 | Asian elephant | 3.9 h/day | – | 2547 | Proboscidea | herbi |
| 10 | Cow | 4.0 h/day | 0.7 | 600 | Artiodactyla | herbi |
| 11 | Brazilian tapir | 4.4 h/day | 1 | 207.501 | Perissodactyla | herbi |
| 12 | Bottle-nosed dolphin | 5.2 h/day | – | 173.33 | Cetacea | carni |
| 13 | Goat | 5.3 h/day | 0.6 | 33.5 | Artiodactyla | herbi |
| 14 | Tree hyrax | 5.3 h/day | 0.5 | 2.95 | Hyracoidea | herbi |
| 15 | Rock hyrax | 5.4 h/day | 0.5 | 3.6 | Hyracoidea | – |
| 16 | Common porpoise | 5.6 h/day | – | 53.18 | Cetacea | carni |
| 17 | Gray seal | 6.2 h/day | 1.5 | 85 | Carnivora | carni |
| 18 | Gray hyrax | 6.3 h/day | 0.6 | 2.625 | Hyracoidea | herbi |
| 19 | Genet | 6.3 h/day | 1.3 | 2 | Carnivora | carni |
| 20 | Vesper mouse | 7.0 h/day | – | 0.045 | Rodentia | – |
| 21 | Degu | 7.7 h/day | 0.9 | 0.21 | Rodentia | herbi |
| 22 | Human | 8.0 h/day | 1.9 | 62 | Primates | omni |
| 23 | African giant pouched rat | 8.3 h/day | 2 | 1 | Rodentia | omni |
| 24 | Rabbit | 8.4 h/day | 0.9 | 2.5 | Lagomorpha | herbi |
| 25 | Eastern american mole | 8.4 h/day | 2.1 | 0.075 | Soricomorpha | insecti |
| 26 | Short-nosed echidna | 8.6 h/day | – | 4.5 | Monotremata | insecti |
| 27 | Northern fur seal | 8.7 h/day | 1.4 | 20.49 | Carnivora | carni |
| 28 | African striped mouse | 8.7 h/day | – | 0.044 | Rodentia | omni |
| 29 | Tree shrew | 8.9 h/day | 2.6 | 0.104 | Scandentia | omni |
| 30 | Lesser short-tailed shrew | 9.1 h/day | 1.4 | 0.005 | Soricomorpha | omni |
| 31 | Pig | 9.1 h/day | 2.4 | 86.25 | Artiodactyla | omni |
| 32 | Guinea pig | 9.4 h/day | 0.8 | 0.728 | Rodentia | herbi |
| 33 | Baboon | 9.4 h/day | 1 | 25.235 | Primates | omni |
| 34 | Mongoose lemur | 9.5 h/day | 0.9 | 1.67 | Primates | herbi |
| 35 | Squirrel monkey | 9.6 h/day | 1.4 | 0.743 | Primates | omni |
| 36 | Chimpanzee | 9.7 h/day | 1.4 | 52.2 | Primates | omni |
| 37 | Galago | 9.8 h/day | 1.1 | 0.2 | Primates | omni |
| 38 | Red fox | 9.8 h/day | 2.4 | 4.23 | Carnivora | carni |
| 39 | Grivet | 10.0 h/day | 0.7 | 4.75 | Primates | omni |
| 40 | Dog | 10.1 h/day | 2.9 | 14 | Carnivora | carni |
| 41 | European hedgehog | 10.1 h/day | 3.5 | 0.77 | Erinaceomorpha | omni |
| 42 | Macaque | 10.1 h/day | 1.2 | 6.8 | Primates | omni |
| 43 | Star-nosed mole | 10.3 h/day | 2.2 | 0.06 | Soricomorpha | omni |
| 44 | Desert hedgehog | 10.3 h/day | 2.7 | 0.55 | Erinaceomorpha | – |
| 45 | Jaguar | 10.4 h/day | – | 100 | Carnivora | carni |
| 46 | Mole rat | 10.6 h/day | 2.4 | 0.122 | Rodentia | – |
| 47 | Patas monkey | 10.9 h/day | 1.1 | 10 | Primates | omni |
| 48 | Slow loris | 11.0 h/day | – | 1.4 | Primates | carni |
| 49 | Potto | 11.0 h/day | – | 1.1 | Primates | omni |
| 50 | Potoroo | 11.1 h/day | 1.5 | 1.1 | Diprotodontia | herbi |
| 51 | Cotton rat | 11.3 h/day | 1.1 | 0.148 | Rodentia | herbi |
| 52 | Deer mouse | 11.5 h/day | – | 0.021 | Rodentia | – |
| 53 | Cheetah | 12.1 h/day | – | 50 | Carnivora | carni |
| 54 | Chinchilla | 12.5 h/day | 1.5 | 0.42 | Rodentia | herbi |
| 55 | Domestic cat | 12.5 h/day | 3.2 | 3.3 | Carnivora | carni |
| 56 | House mouse | 12.5 h/day | 1.4 | 0.022 | Rodentia | herbi |
| 57 | Arctic fox | 12.5 h/day | – | 3.38 | Carnivora | carni |
| 58 | Vole | 12.8 h/day | – | 0.035 | Rodentia | herbi |
| 59 | Musk shrew | 12.8 h/day | 2 | 0.048 | Soricomorpha | – |
| 60 | Laboratory rat | 13.0 h/day | 2.4 | 0.32 | Rodentia | herbi |
| 61 | Lion | 13.5 h/day | – | 161.499 | Carnivora | carni |
| 62 | Phalanger | 13.7 h/day | 1.8 | 1.62 | Diprotodontia | – |
| 63 | Thirteen-lined ground squirrel | 13.8 h/day | 3.4 | 0.101 | Rodentia | herbi |
| 64 | Mongolian gerbil | 14.2 h/day | 1.9 | 0.053 | Rodentia | herbi |
| 65 | Golden hamster | 14.3 h/day | 3.1 | 0.12 | Rodentia | herbi |
| 66 | Mountain beaver | 14.4 h/day | 2.4 | 1.35 | Rodentia | herbi |
| 67 | Three-toed sloth | 14.4 h/day | 2.2 | 3.85 | Pilosa | herbi |
| 68 | Northern grasshopper mouse | 14.5 h/day | – | 0.028 | Rodentia | carni |
| 69 | Round-tailed muskrat | 14.6 h/day | – | 0.266 | Rodentia | herbi |
| 70 | Greater short-tailed shrew | 14.9 h/day | 2.3 | 0.019 | Soricomorpha | omni |
| 71 | Western american chipmunk | 14.9 h/day | – | 0.071 | Rodentia | herbi |
| 72 | Tenrec | 15.6 h/day | 2.3 | 0.9 | Afrosoricida | omni |
| 73 | Tiger | 15.8 h/day | – | 162.564 | Carnivora | carni |
| 74 | Eastern american chipmunk | 15.8 h/day | – | 0.112 | Rodentia | herbi |
| 75 | Golden-mantled ground squirrel | 15.9 h/day | 3 | 0.205 | Rodentia | herbi |
| 76 | Arctic ground squirrel | 16.6 h/day | – | 0.92 | Rodentia | herbi |
| 77 | Owl monkey | 17.0 h/day | 1.8 | 0.48 | Primates | omni |
| 78 | Long-nosed armadillo | 17.4 h/day | 3.1 | 3.5 | Cingulata | carni |
| 79 | North American Opossum | 18.0 h/day | 4.9 | 1.7 | Didelphimorphia | omni |
| 80 | Giant armadillo | 18.1 h/day | 6.1 | 60 | Cingulata | insecti |
| 81 | Thick-tailed opposum | 19.4 h/day | 6.6 | 0.37 | Didelphimorphia | carni |
| 82 | Big brown bat | 19.7 h/day | 3.9 | 0.023 | Chiroptera | insecti |
| 83 | Little brown bat | 19.9 h/day | 2 | 0.01 | Chiroptera | insecti |

The bottom of the table belongs to big grazers: giraffe (1.9 h), horse (2.9 h), roe deer (3.0 h), donkey (3.1 h) and
African elephant (3.3 h). A common explanation is that grazing on low-energy food leaves little time for anything
else, but the main pattern in the data is simply size.

One entry needs care: the pilot whale's 2.7 hours (and the dolphin's and porpoise's figures) were halved by Savage &
West because these animals sleep with one brain hemisphere at a time. They are not comparable behavioural sleep
times, and each row says so. Wild African elephants, measured with trunk sensors, slept even less than the
captive figure here: about [2 hours a day](https://karelbusta.dev/data/sleep/wild-elephants-sleep-2-hours).

## Source

- Savage & West (2007), PNAS: https://doi.org/10.1073/pnas.0610080104 (sample: 83 mammal species)
- Dataset with methodology and CSV/JSON downloads: https://karelbusta.dev/data/sleep/datasets/mammal-sleep

## Related facts

- [Wild elephants sleep about 2 hours a day](https://karelbusta.dev/data/sleep/wild-elephants-sleep-2-hours)
- [The bigger the mammal, the less it sleeps](https://karelbusta.dev/data/sleep/bigger-animals-sleep-less)
- [Frigatebirds sleep in mid-air, about 40 minutes a day](https://karelbusta.dev/data/sleep/frigatebirds-sleep-in-flight)