Table 1.

Dataset used in this study. (Values refer to both hemispheres together. Daily sleep hours from [7]. When more than one estimate was available, the value presented here is the average for the species. For the other columns, numbers in parentheses refer to references in the main text. DNCX, neuronal density in the cerebral cortical grey matter, except where indicated with an asterisk (*) (density includes the white matter), in neurons mg−1 (our own data) or neurons mm−3 (data taken from other authors). ACX, total surface area of the cerebral cortex (in mm2). D/A, ratio between neuronal density in the cerebral cortex (in neurons mg−1) and total cortical surface area (in mm2). NCX, number of neurons in the cerebral cortex. O/N, ratio between numbers of other cells (non-neuronal cells, presumed to be mostly glial cells) and neurons in the cortical grey matter, except where indicated with an asterisk (*) (ratio includes the white matter). T, thickness of the cortical grey matter( in mm), from VCX/ACX. MCX, mass (in g, our data) or volume (in cm3) of the cortical grey matter, except where indicated with an asterisk (*) (mass includes white matter). n.a., not available.)

speciesbrain mass (g or cm3)daily sleep (h)D/A (N mg−1 mm−2)NCXDNCX (N mg−1)ACX (mm2)O/NTMCX (g or cm3)
Primates
Aotus trivirgatus15.750 [19]16.9710.831441.90 × 106 [20]47 960 [20]4428 [20]1.340 [20]1.6707.396 [20]
Callithrix sp.7.780 [19]10.2217.679244.72 × 106 [20]54 240 [20]3068 [20]1.114 [20]1.3314.084 [20]
Cebus apella52.508 [19]5.953.3371.14 × 109 [20]51 080 [20]15 306 [20]1.106 [20]2.06731.640 [20]
Saimiri sciureus30.216 [19]9.117.7071.34 × 109 [19]80 920 [20]10 500 [20]0.768 [20]1.33313.992 [20]
Macaca mulatta87.346 [19]8.741.2841.71 × 109 [19]32 110 [20]25 000 [15]2.011 [20]1.71442.860 [19]
Macaca radiata61.470 [25]9.022.5951.66 × 109 [20]43 810 [20]16 882 [20]1.278 [20]1.83530.986 [20]
Papio cynocephalus151.190 [25]6.191.0112.88 × 109 [20]33 730 [20]33 378 [20]1.317 [20]2.17772.668 [20]
Homo sapiens1509 [24]8.470.11416.34 × 109 [24]21 450 [24]188 100 [29]1.480 [29]2.938552.7 [29]
Eulipotyphla
Blarina brevicauda0.340 [23]14.90271.92711.88 × 106 [23]59 280* [23]218a1.000* [23]0.8210.179* [23]
Condylura cristata0.802 [23]10.32106.83217.25 × 106 [23]38 780* [23]363a1.924* [23]1.0720.389* [23]
Erinaceus europaeus3.230 [15]13.9629.22133.53 × 106b27 000 [48]924 [15]2.214 [48]1.0470.967 [15]
Scalopus aquaticus0.999 [23]8.45168.29128.68 × 106 [23]60 252* [23]357a1.296* [23]1.0700.382* [23]
Glires
Cavia porcellus3.656 [26]9.3720.72943.51 × 106 [26]22 222 [26]1072 [26]2.606 [26]1.8271.959 [26]
Mesocricetus auratus0.965 [18]14.9898.98517.14 × 106 [18]39 099* [18]395a2.507 [18]1.1290.446* [18]
Mus musculus0.402 [26]11.6046.31613.69 × 106 [18]122 232 [26]296 [4]0.870 [26]0.7240.214 [26]
Oryctolagus cuniculus7.100 [15]9.5531.73971.45 × 106 [21]43 800 [47]1380 [15]3.566n.a.n.a.
Rattus norvegicus1.724 [26]12.2749.68531.02 × 106 [18]35 330 [26]711 [4]1.497 [26]1.2120.862 [26]
Afrotheria
Dendrohyrax sp.3.328 [27]5.406.30898.97 × 106 [27]12 709 [27]3791 [27]1.426 [27]1.5986.058 [27]
Loxodonta Africana4618 [22]3.300.0075.59 × 109 [22]3661 [22]514 134 [22]10.628 [22]2.6331353.9 [22]
Procavia sp.4.317 [27]5.454.920197.92 × 106 [27]20 794 [27]4226 [27]1.241 [27]1.4826.263 [27]
Artiodactyla
Bos taurus486 [15]3.190.1231.34 × 109c13 000 [47]105 500 [15]4.085 [47]2.142226.0 [15]
Giraffa camelopardalis537 [28]3.440.0731.73 × 109 [28]5882 [28]80 256 [28]7.763 [28]2.394192.1 [28]
Sus scrofa64.180 [28]8.200.559307.08 × 106 [28]7375 [28]13 188 [28]8.543 [28]1.336 [28]17.614 [28]
Scandentia
Tupaia sp.3.040 [15]15.8429.45760.39 × 106 [19]38 000 [48]1290 [15]1.511 [20]0.7981.030 [20]
  • aValues estimated as 7.34118 × VCX0.654, according to [15].

  • bValue estimated from cortical mass according to [30].

  • cValue estimated from brain mass according to [28].