Encephalization in vertebrates. A new mode of calculation for allometry coefficients and isoponderal indices.
The conventional allometric power function, with its slope near 2/3, works well for interspecific scaling of brain vs. body weight in all groups of vertebrates. It fails, however, in extrapolation to vertebrates of the largest size within their groups: these have smaller brains than the equation would predict. We propose a correction, the hyperbolic tangent, to linearize the data over all sizes, and we discuss evolutionary reasons for the relatively small brain size of the largest vertebrates.
D000717:Anatomy, Comparative; D000818:Animals; D005075:Biological Evolution; D001835:Body Weight; D001921:Brain / Q000033:anatomy & histology*; D009929:Organ Size; D013045:Species Specificity; D014714:Vertebrates / Q000033:anatomy & histology*