The population of rock wallabies (genus Petrogale) on Oahu,Hawaii

A population of peculiar rock wallabies (Macropodidae: Petrogale) became established in the Ko'olau Range, Oahu, in 1916. The few available specimens differ from known Australian forms in skull characters, size, and electrophoretic profile. The population seems largely confined to ca 7·0 ha in one valley from ca 150–400 m, on a mean slope of 60°. There were ca 53 (range 27–94, p = 0·05) individuals in a grid of 1·5 ha, indicating a population of 247 (126–439) animals. The sex ratio was 1:3 males:females. Fifty per cent of females over 89 cm were carrying or nursing joeys during November. Seemingly old, blind, post-reproductive individuals of both sexes were present and all individuals appeared robust. There was no significant size difference between the sexes. The taxonomic status of these animals is under study.