A morphometric trend linked to male sociality in the small Indian mongoose Herpestes javanicus in Hawaii

Introduced populations of the small Indian mongoose Herpestes javanicus (Geoffroy St. Hilaire, 1818), in Hawaii have been shown to include male breeding coalitions. Young individuals of this species stay with their mothers until they reach adult size, suggesting that young males are not exposed to the full pressure of intrasexual competition until they have completed skeletal development. It was hypothesized that variance of male skeletal characteristics should therefore be similar to the variance seen in females. It has been observed that adult males with small body mass are not typically members of breeding coalitions, suggesting that body mass is a key factor in male intraspecific competition. It was thus hypothesized that variance in male mass should exceed that in female mass. These hypotheses were tested by direct measurement of live animals in the field and by measurement of museum specimens. Both hypotheses were strongly supported. A significant correlation was also found between male body length and variance in male mass, but no correlation was found among females. It is suggested that males with low body length, like females, maintain only as much mass as is physiologically required, whereas long males maximize their mass with varying degrees of success, to facilitate intrasexual competition.