Varanus gouldii has a strongly seasonal period of activity in the Great Victoria desert, being active only during the warm six months from September through February (it is completely inactive from March through August, Pianka 1970b, 1994). Both sexes achieve sexual maturity at snout-vent lengths of about 250 mm. Mating occurs in November and December. Clutch size averages 6.2 eggs, which are laid in the Austral summer. Hatchlings emerge during December, January, and February and measure from 101 mm to 118 mm in snout-vent length.
V. gouldii capture most of their prey (predominantly lizards and reptile eggs) by digging; these lizards appear to have a very keen sense of olfaction, using their long, forked, and very snake-like tongues extensively (Pianka 1970b). Geckos are important prey (dug up in their diurnal retreats), but many diurnal species of lizards are also eaten (Ctenophorus, Ctenotus, Lerista, Lialis, Menetia, Moloch, Pogona, as well as other Varanus, including brevicauda, caudolineatus, gilleni and gouldi). They also eat reptile eggs, baby mammals and baby birds. These lizards very probably eat any other lizard that they can catch. Among specimens I have examined, the largest relative prey mass was a Pogona minor estimated to weigh about 25 gms eaten by a gouldi that weighed 180 gms, about 13.9%.
Pianka, E. R. 1970. Notes on the biology of Varanus gouldii flavirufus. Western Australian Naturalist 11: 141-144. Download pdf
Pianka, E. R. 1982. Observations on the ecology of Varanus in the Great Victoria desert. Western Australian Naturalist 15: 37-44. Download pdf
Pianka, E. R. 1994. Comparative ecology of Varanus in the Great Victoria desert. Australian Journal of Ecology 19: 395-408. Download pdf.
To read about other Varanus in the Great Victoria desert of Western Australia, click Desert Varanus.