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 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.