Dataset from Allison and Cicchetti (1976) of 62 mammal species on the interrelationship between sleep, ecological, and constitutional variables. The dataset contains missing values on five variables.
mammalsleep is a data frame with 62 rows and 11 columns:
Species of animal
Body weight (kg)
Brain weight (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 = least 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)
Allison, T., Cicchetti, D.V. (1976). Sleep in Mammals: Ecological and Constitutional Correlates. Science, 194(4266), 732-734.
Allison and Cicchetti (1976) investigated the interrelationship between sleep, ecological, and constitutional variables. They assessed these variables for 39 mammalian species. The authors concluded that slow-wave sleep is negatively associated with a factor related to body size. This suggests that large amounts of this sleep phase are disadvantageous in large species. Also, paradoxical sleep (REM sleep) was associated with a factor related to predatory danger, suggesting that large amounts of this sleep phase are disadvantageous in prey species.
sleep <- data(mammalsleep)