openintro (version 2.4.0)

mammals: Sleep in Mammals

Description

This data set includes data for 39 species of mammals distributed over 13 orders. The data were used for analyzing the relationship between constitutional and ecological factors and sleeping in mammals. Two qualitatively different sleep variables (dreaming and non dreaming) were recorded. Constitutional variables such as life span, body weight, brain weight and gestation time were evaluated. Ecological variables such as severity of predation, safety of sleeping place and overall danger were inferred from field observations in the literature.

Usage

mammals

Format

A data frame with 62 observations on the following 11 variables.

species

Species of mammals

body_wt

Total body weight of the mammal (in kg)

brain_wt

Brain weight of the mammal (in kg)

non_dreaming

Number of hours of non dreaming sleep

dreaming

Number of hours of dreaming sleep

total_sleep

Total number of hours of sleep

life_span

Life span (in years)

gestation

Gestation time (in days)

predation

An index of how likely the mammal is to be preyed upon. 1 = least likely to be preyed upon. 5 = most likely to be preyed upon.

exposure

An index of the how exposed the mammal is during sleep. 1 = least exposed (e.g., sleeps in a well-protected den). 5 = most exposed.

danger

An index of how much danger the mammal faces from other animals. This index is based upon Predation and Exposure. 1 = least danger from other animals. 5 = most danger from other animals.

References

T. Allison and D. Cicchetti, "Sleep in mammals: ecological and constitutional correlates," Arch. Hydrobiol, vol. 75, p. 442, 1975.

Examples

library(ggplot2)

ggplot(mammals, aes(x = log(body_wt), y = log(brain_wt))) +
  geom_point() +
  geom_smooth(method = "lm") +
  labs(x = "Log of body weight", x = "Log of brain weight")