Heart weight as a function of body weight in mammals

Linear regression analysis was carried out on logarithmically transformed heart weight and body weight data in 104 mammalian species. It was shown that heart weight varies as the 0.98 power of body weight over essentially the whole mammalian weight range. The coefficient of correlation between heart weight and body weight is 0.99. Student's test was employed to compare the slopes of the several regression lines as between male and female animals, and as between terrestrial and aquatic mammals. In neither case were the differences in slope found to be statistically significant (df greater than 177, p less than 0.5).