The introduction of the toxic cane toad (Rhinella marina) to central Queensland in 1935, and its subsequent spread across northern Australia, has caused massive declines in native naïve predator numbers such as yellow-spotted goannas (Varanus panoptes). Attempting to feed on the toxic toads leads to cardiac arrest and ultimately death of these large carnivorous lizards. A long-term ongoing study (initiated in 2001) of yellow-spotted goannas conducted on the Adelaide River Floodplain in the NT has shown population declines of more than 90% coinciding with arrival of the cane toads in 2005. Surprisingly, population genetic analyses of the TLR4 gene as well as 8 microsatellite markers do not show any loss of genetic diversity of the few surviving yellow-spotted goannas 10 years after the decline. Consequently, the next stage of the study will focus on elucidating whether the observed high genetic diversity in post decline goannas is caused by the extremely high pre-decline genetic diversity and/or by migration of goannas into the study area from adjacent habitats. In addition the study will investigate the evolutionary and molecular mechanisms that allow the yellow-spotted goanna populations persisting in Queensland to co-exist with cane toads for >70 years.