A natural grey kangaroo hybrid?

The eastern grey kangaroo, Macropus giganteus, and the western grey kangaroo, M. fuliginosus, occur over an extensive zone of sympatry, but there has been no record of hybridisation between these sibling species in the field. The two species can be reliably distinguished by their characteristic pelage, which is grey-brown in eastern grey kangaroos and chocolate brown in western grey kangaroos. The pattern of colour on the face is particularly distinctive: the pale grey face of the eastern grey kangaroo contrasts with dark shading around the eyes, whereas the western grey kangaroo has a monochrome dark brown face. We report a sighting of a probable hybrid grey kangaroo in June 2000 at Willandra National Park (33° 13’ S, 145° 07’ E), western New South Wales. This individual was an adult female, which was intermediate in phenotype and was accompanied by a possible back-crossed sub-adult. In view of this and other reports of putative hybrids, we urge greater scrutiny of grey kangaroos in the sympatric zone.