Data from which conclusions were drawn in the article "Sleep in Mammals: Ecological and Constitutional Correlates" by Allison, T. and Cicchetti, D. (1976), _Science_, November 12, vol. 194, pp. 732-734. Includes brain and body weight, life span, gestation time, time sleeping, and predation and danger indices for 62 mammals. Variables below (from left to right) for Mammals Data Set: species of animal body weight in kg brain weight in g slow wave ("nondreaming") sleep (hrs/day) paradoxical ("dreaming") sleep (hrs/day) total sleep (hrs/day) (sum of slow wave and paradoxical sleep) maximum life span (years) gestation time (days) predation index (1-5) 1 = minimum (least likely to be preyed upon) 5 = maximum (most likely to be preyed upon) sleep exposure index (1-5) 1 = least exposed (e.g. animal sleeps in a well-protected den) 5 = most exposed overall danger index (1-5) (based on the above two indices and other information) 1 = least danger (from other animals) 5 = most danger (from other animals) Note: Missing values denoted by '.' For more details, see Allison, Truett and Cicchetti, Domenic V. (1976), "Sleep in Mammals: Ecological and Constitutional Correlates", _Science_, November 12, vol. 194, pp. 732-734. Excerpt... African_elephant 6654.000 5712.00 . . 3.3 38.6 645 3 5 3 African_giant_pouched_rat 1.000 6.60 6.3 2.0 8.3 4.5 42 3 1 3 Arctic_Fox 3.385 44.50 . . 12.5 14.0 60 1 1 1 Arctic_ground_squirrel .920 5.70 . . 16.5 . 25 5 2 3 Asian_elephant 2547.000 4603.00 2.1 1.8 3.9 69.0 624 3 5 4 ... ... Tree_hyrax 2.000 12.30 4.9 .5 5.4 7.5 200 3 1 3 Tree_shrew .104 2.50 13.2 2.6 15.8 2.3 46 3 2 2 Vervet 4.190 58.00 9.7 .6 10.3 24.0 210 4 3 4 Water_opossum 3.500 3.90 12.8 6.6 19.4 3.0 14 2 1 1 Yellow_bellied_marmot 4.050 17.00 . . . 13.0 38 3 1 1 The above data set can be freely used for non-commercial purposes and can be freely distributed (permission in writing obtained from Dr. Truett Allison). Submitted by Roger Johnson rjohnson@carleton.edu