Dataset
Sleep in mammals
Daily total and REM sleep, sleep-cycle length, brain and body weight for 83 mammal species, from Savage & West (2007) via ggplot2's msleep.
- Source
- Savage & West (2007), PNASSavage VM, West GB. A quantitative, theoretical framework for understanding mammalian sleep. Proc Natl Acad Sci USA. 2007;104(3):1051–1056. doi:10.1073/pnas.0610080104
- Sample
- 83 mammal species
- Coverage
- 83 mammal species across 19 orders; measurements compiled from laboratory and captive-animal sleep studies published up to 1989
- License
- The msleep file is distributed with ggplot2 under the MIT License (Copyright (c) 2025 ggplot2 core developer team), https://github.com/tidyverse/ggplot2/blob/737be17f43bebac02ccb119753c1fee267572443/LICENSE.md. The measurements themselves are factual data compiled from published papers (Savage & West 2007, who took sleep times from Zepelin 1989 and body/brain masses mainly from Meddis 1983).
- Retrieved
- October 14, 2026
- Download
- All tables (JSON)Sleep by species (CSV)Bigger mammals sleep less: log-log fit (CSV)
- See also
Caveats
- Almost all values come from EEG recordings of captive or laboratory animals; sleep in the wild can differ a lot.
- Wild brown-throated three-toed sloths slept 9.63 h/day on EEG, over 6 h less than previously reported in captivity (Rattenborg et al. 2008); msleep lists 14.4 h.
- Dolphin, pilot whale and porpoise totals were halved by Savage & West because these whales sleep one brain hemisphere at a time; they are not behavioural sleep times.
- Diet (vore), order and conservation status were added by ggplot2 from Wikipedia around 2015, not by the paper, and conservation codes are not current IUCN assessments.
- Some genus names are misspelled in the source (Capri, Cavis, Haliochoerus, Nyctibeus) and are kept as published.
- Pilot whale and common porpoise: sleep_total + awake = 24.05 h, so one of the two is rounded.
- Values were not cross-checked against the paper's supplementary Table 1, which could not be downloaded (see Methodology).
Built from this dataset
Sleep by species
One row per species (83). Values exactly as in ggplot2's msleep.csv (Savage & West 2007 sleep times and weights; order, vore and conservation added by ggplot2 from Wikipedia). Empty = not reported.
| Species | Genus | Order | Diet | Conservation | Total sleep (h/day) | REM sleep (h/day) | Sleep cycle (h) | Awake (h/day) | Brain weight (kg) | Body weight (kg) | Note |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Cheetah | Acinonyx | Carnivora | carni | lc | 12.1 | – | – | 11.9 | – | 50 | – |
| Owl monkey | Aotus | Primates | omni | – | 17 | 1.8 | – | 7 | 0.02 | 0.48 | – |
| Mountain beaver | Aplodontia | Rodentia | herbi | nt | 14.4 | 2.4 | – | 9.6 | – | 1.35 | – |
| Greater short-tailed shrew | Blarina | Soricomorpha | omni | lc | 14.9 | 2.3 | 0.13 | 9.1 | 0 | 0.02 | – |
| Cow | Bos | Artiodactyla | herbi | domesticated | 4 | 0.7 | 0.67 | 20 | 0.42 | 600 | – |
| Three-toed sloth | Bradypus | Pilosa | herbi | – | 14.4 | 2.2 | 0.77 | 9.6 | – | 3.85 | – |
| Northern fur seal | Callorhinus | Carnivora | carni | vu | 8.7 | 1.4 | 0.38 | 15.3 | – | 20.49 | – |
| Vesper mouse | Calomys | Rodentia | – | – | 7 | – | – | 17 | – | 0.05 | – |
| Dog | Canis | Carnivora | carni | domesticated | 10.1 | 2.9 | 0.33 | 13.9 | 0.07 | 14 | – |
| Roe deer | Capreolus | Artiodactyla | herbi | lc | 3 | – | – | 21 | 0.1 | 14.8 | – |
| Goat | Capri | Artiodactyla | herbi | lc | 5.3 | 0.6 | – | 18.7 | 0.12 | 33.5 | – |
| Guinea pig | Cavis | Rodentia | herbi | domesticated | 9.4 | 0.8 | 0.22 | 14.6 | 0.01 | 0.73 | – |
| Grivet | Cercopithecus | Primates | omni | lc | 10 | 0.7 | – | 14 | – | 4.75 | – |
| Chinchilla | Chinchilla | Rodentia | herbi | domesticated | 12.5 | 1.5 | 0.12 | 11.5 | 0.01 | 0.42 | – |
| Star-nosed mole | Condylura | Soricomorpha | omni | lc | 10.3 | 2.2 | – | 13.7 | 0 | 0.06 | – |
| African giant pouched rat | Cricetomys | Rodentia | omni | – | 8.3 | 2 | – | 15.7 | 0.01 | 1 | – |
| Lesser short-tailed shrew | Cryptotis | Soricomorpha | omni | lc | 9.1 | 1.4 | 0.15 | 14.9 | 0 | 0.01 | – |
| Long-nosed armadillo | Dasypus | Cingulata | carni | lc | 17.4 | 3.1 | 0.38 | 6.6 | 0.01 | 3.5 | – |
| Tree hyrax | Dendrohyrax | Hyracoidea | herbi | lc | 5.3 | 0.5 | – | 18.7 | 0.01 | 2.95 | – |
| North American Opossum | Didelphis | Didelphimorphia | omni | lc | 18 | 4.9 | 0.33 | 6 | 0.01 | 1.7 | – |
| Asian elephant | Elephas | Proboscidea | herbi | en | 3.9 | – | – | 20.1 | 4.6 | 2,547 | – |
| Big brown bat | Eptesicus | Chiroptera | insecti | lc | 19.7 | 3.9 | 0.12 | 4.3 | 0 | 0.02 | – |
| Horse | Equus | Perissodactyla | herbi | domesticated | 2.9 | 0.6 | 1 | 21.1 | 0.66 | 521 | – |
| Donkey | Equus | Perissodactyla | herbi | domesticated | 3.1 | 0.4 | – | 20.9 | 0.42 | 187 | – |
| European hedgehog | Erinaceus | Erinaceomorpha | omni | lc | 10.1 | 3.5 | 0.28 | 13.9 | 0 | 0.77 | – |
| Patas monkey | Erythrocebus | Primates | omni | lc | 10.9 | 1.1 | – | 13.1 | 0.12 | 10 | – |
| Western american chipmunk | Eutamias | Rodentia | herbi | – | 14.9 | – | – | 9.1 | – | 0.07 | – |
| Domestic cat | Felis | Carnivora | carni | domesticated | 12.5 | 3.2 | 0.42 | 11.5 | 0.03 | 3.3 | – |
| Galago | Galago | Primates | omni | – | 9.8 | 1.1 | 0.55 | 14.2 | 0.01 | 0.2 | – |
| Giraffe | Giraffa | Artiodactyla | herbi | cd | 1.9 | 0.4 | – | 22.1 | – | 900 | – |
| Pilot whale | Globicephalus | Cetacea | carni | cd | 2.7 | 0.1 | – | 21.35 | – | 800 | Cetacean: total sleep was halved by Savage & West (2007) to account for unihemispheric sleep |
| Gray seal | Haliochoerus | Carnivora | carni | lc | 6.2 | 1.5 | – | 17.8 | 0.33 | 85 | – |
| Gray hyrax | Heterohyrax | Hyracoidea | herbi | lc | 6.3 | 0.6 | – | 17.7 | 0.01 | 2.63 | – |
| Human | Homo | Primates | omni | – | 8 | 1.9 | 1.5 | 16 | 1.32 | 62 | – |
| Mongoose lemur | Lemur | Primates | herbi | vu | 9.5 | 0.9 | – | 14.5 | – | 1.67 | – |
| African elephant | Loxodonta | Proboscidea | herbi | vu | 3.3 | – | – | 20.7 | 5.71 | 6,654 | – |
| Thick-tailed opposum | Lutreolina | Didelphimorphia | carni | lc | 19.4 | 6.6 | – | 4.6 | – | 0.37 | – |
| Macaque | Macaca | Primates | omni | – | 10.1 | 1.2 | 0.75 | 13.9 | 0.18 | 6.8 | – |
| Mongolian gerbil | Meriones | Rodentia | herbi | lc | 14.2 | 1.9 | – | 9.8 | – | 0.05 | – |
| Golden hamster | Mesocricetus | Rodentia | herbi | en | 14.3 | 3.1 | 0.2 | 9.7 | 0 | 0.12 | – |
| Vole | Microtus | Rodentia | herbi | – | 12.8 | – | – | 11.2 | – | 0.04 | – |
| House mouse | Mus | Rodentia | herbi | nt | 12.5 | 1.4 | 0.18 | 11.5 | 0 | 0.02 | – |
| Little brown bat | Myotis | Chiroptera | insecti | – | 19.9 | 2 | 0.2 | 4.1 | 0 | 0.01 | – |
| Round-tailed muskrat | Neofiber | Rodentia | herbi | nt | 14.6 | – | – | 9.4 | – | 0.27 | – |
| Slow loris | Nyctibeus | Primates | carni | – | 11 | – | – | 13 | 0.01 | 1.4 | – |
| Degu | Octodon | Rodentia | herbi | lc | 7.7 | 0.9 | – | 16.3 | – | 0.21 | – |
| Northern grasshopper mouse | Onychomys | Rodentia | carni | lc | 14.5 | – | – | 9.5 | – | 0.03 | – |
| Rabbit | Oryctolagus | Lagomorpha | herbi | domesticated | 8.4 | 0.9 | 0.42 | 15.6 | 0.01 | 2.5 | – |
| Sheep | Ovis | Artiodactyla | herbi | domesticated | 3.8 | 0.6 | – | 20.2 | 0.18 | 55.5 | – |
| Chimpanzee | Pan | Primates | omni | – | 9.7 | 1.4 | 1.42 | 14.3 | 0.44 | 52.2 | – |
First 50 of 83 rows. Download all as CSV
Bigger mammals sleep less: log-log fit
Ordinary least squares fit of log10(total sleep, h/day) on log10(body weight, kg), computed by build.ts from the species table. sleep ≈ sleep_at_1kg × bodywt^slope.
| Model | Species | Slope | Slope 95% CI low | Slope 95% CI high | Intercept (log10) | R² | Predicted sleep at 1 kg (h/day) | Sleep ratio per 10× mass |
|---|---|---|---|---|---|---|---|---|
| All species | 83 | -0.1 | -0.13 | -0.08 | 1.01 | 0.4 | 10.13 | 0.79 |
| Excluding 3 cetaceans with halved sleep | 80 | -0.1 | -0.13 | -0.07 | 1.01 | 0.36 | 10.21 | 0.8 |
2 rows. Download all as CSV
Methodology
What was measured
Savage & West (2007) compiled daily sleep for 83 mammal species to test a metabolic-scaling theory of sleep. Per their Methods, all sleep data (total sleep, REM sleep, sleep-cycle length) come from Zepelin's compilation (Zepelin 1989, in Principles and Practice of Sleep Medicine, 2nd ed.), which aggregates EEG/behavioural sleep studies, almost all of animals in captivity or the laboratory. Body masses come mostly from Meddis (1983), with Smith et al. (2003) and Nowak (1991, Walker's Mammals of the World) used when a value was missing; brain masses come from Meddis, with two values excluded because their sleep values did not match Zepelin's. They also:
- divided total sleep by two for the bottlenose dolphin (Tursiops truncatus), pilot whale (Globicephalus scammoni) and harbour porpoise (Phocoena phocoena), because these cetaceans sleep with one hemisphere at a time;
- excluded REM data for the dolphin and porpoise, REM and cycle length for the Asian elephant (flagged doubtful in the source), and the 0.0 REM value for the short-nosed echidna.
The ggplot2 maintainers published these values as the msleep dataset ("an updated and expanded version of the
mammals sleep dataset", the original being Allison & Cicchetti 1976, Science 194:732–734) and added order, diet
(vore) and conservation status from Wikipedia.
Source file
apps/data/ingest/mammal-sleep/fetch.ts downloads data-raw/msleep.csv from tidyverse/ggplot2 pinned at commit
737be17f43bebac02ccb119753c1fee267572443 (5,993 bytes, sha256 6589d852…d7cd3; full hash in manifest.json). The
file has not changed since commit 72122706 (2015-06-17). The paper's own supplementary Table 1
(pnas_0610080104_10080Table1.xls) is listed on PubMed Central but could not be fetched by script (reCAPTCHA on PMC,
HTTP 403 on pnas.org, not in the Europe PMC open-access subset, no Wayback snapshot), so the msleep values were not
cross-checked row by row against it.
Processing
build.ts reads the committed CSV, checks its sha256 against the manifest, and writes two tables:
- species: the 83 rows with every number exactly as in the CSV (
NAbecomes empty/null). The only change is trimming surrounding whitespace in text fields (the source has"Vole "). Anotecolumn marks the three cetaceans whose sleep was halved. - allometry: an ordinary least squares fit of log10(total sleep, h/day) on log10(body weight, kg), with a 95% confidence interval for the slope from the t distribution (n − 2 degrees of freedom). Over all 83 species the slope is −0.103 (95% CI −0.130 to −0.075), R² = 0.40, i.e. each tenfold increase in body weight goes with about 21% less sleep, from roughly 10 h/day at 1 kg. Dropping the three halved cetaceans barely changes it (slope −0.096, n = 80). This matches the paper's statement that the data "give an exponent for t_S of −0.1"; Savage & West's headline slope of −0.16 is for the ratio of sleep to awake time, not total sleep.
Body weight explains only about 40% of the variation (on the log scale): species of similar size can differ by several hours, and diet, predation risk and sleeping site all matter.
Generated October 14, 2026 by apps/data/ingest/mammal-sleep/build.ts in the site's repository.