New flexible growth function and its application to the growth of small mammals.

The function [formula: see text] where a is the upper asympotic weight and b, c, k are constants, is derived as a new flexible growth equation and evaluated using commonly applied growth functions such as Monomelecular, Gompertz, Logistic, Richards, France, Janoschek and Hill. Three sets of observations on growth of small mammal species (Microtus brandti and Ochotona curzoniae) are used to evaluate the fits of these functions. In addition, points of inflexion of these growth equations are also derived in this paper. The new function encompasses the Logistic and Monomolecular equation for different value of parameter b. It provides a flexible growth equation capable of describing smooth sigmoidal and diminishing returns behaviour. The success of the new equation in describing these sets of growth patterns underlines its credentials as a suitable additional growth function.