Eastern Water Dragon

The specific name, lesueurii, is in honor of French naturalist Charles Alexandre Lesueur.

The species was first described by John Edward Gray in 1831 as Lophura lesueurii, from a specimen collected by Lesueur & Péron at "Parramatta" or "Port Jackson". Gray listed three species of Lophura: Cuvier's (Lophura Cuvierii Gray), Lesueur's (Lophura Lesueurii Gray), and beautiful (Lophura Concinna Gray, Physignathus Concinnus Cuvier). Gray separated Physignathus (P. concinnus & P. Lesueurii) from Lophura (L. amboinensis & L. Shawii). The Australian water dragon remained in Physignathus along with the Asian water dragon P. cocincinus until Wells and Wellington published the genus Intellagama in 1985. The subspecies howitii was described by Frederick McCoy in 1884 as "the Gippsland water lizard". According to his description, it differs from the Queensland subspecies in the proportions of the head and the supra-ocular scales. Its sub-specific epithet commemorates geologist and magistrate Alfred William Howitt, who collected three specimens from the upper reaches of the Buchan River and sent them to McCoy. Two of the specimens cannot be located, in the collection of the National Museum of Victoria, which was designated the lectotype by Coventry in 1970.

The Australian water dragon is the only species of the genus Intellagama. There are two subspecies; Intellagama lesueurii lesueurii (eastern water dragon) and Intellagama lesueurii howittii (Gippsland water dragon). The nominate subspecies Intellagama lesueurii lesueurii has a dark band behind its eye and an essentially un-patterned throat that tends towards white and is often immaculate in adult males. Whereas the subspecies Intellagama lesueurii howittii lacks the dark stripe behind the eye and has a patterned throat, which is lightly patterned in females but boldly patterned and coloured in adult males. This patterning usually consists of a dark stripe on either side of its throat, and blotched with orange, yellow or blue towards the centre of the throat. Both subspecies are light greenish grey in overall colour (greener in I. l. howittii), with darker bands running across their back, tail and legs. The water dragon can slowly change skin colour to aid its camouflage. The skin will shed during periods of growth and seasonally to reveal brighter colours in Spring that may aid breeding success.

]] Australian water dragons are extremely shy in the wild, but readily adapt to continual human presence in suburban parks and gardens. They are fast runners and strong climbers. When faced with a potential predator, they seek cover in thick vegetation, or drop from an overhanging branch into water. They are able to swim totally submerged, and rest on the bottom of shallow creeks or lakes for up to 90 minutes, to avoid detection. Both males and females display typical agamid behaviour such as basking, arm-waving and head-bobbing. Fast arm-waving signals dominance, while slow arm-waving signals submission. Males are territorial, and in areas of higher population density, males exhibit displays of aggression toward other males including posturing, chasing and fighting.

Australian water dragons living in cooler Australian climates hibernate over winter. During spring, usually in early October, the female excavates a burrow about deep and lays between 6 and 18 eggs. The nest is usually in sandy or soft soil, in an area open to sun. When the mother has laid the eggs, she backfills the chamber with soil and scatters loose debris over it. Australian water dragons exhibit temperature dependent sex determination; the sex of the hatchlings is determined by the temperature of the nest site. When the young are hatched, they stay near the entrance of the burrow for some time before leaving home. When they finally leave the nest, they tend to group together away from the adult population.

Australian water dragons are prey to carnivorous birds, snakes (such as brown tree snakes, common death adders, lowland copperheads, red-bellied black snakes, and eastern brown snakes), cats, dogs, and foxes. Nestlings and smaller juvenile water dragons are vulnerable to predation by kookaburras, currawongs, butcherbirds and other carnivorous birds. They are also prone to becoming road kill due to the attraction of warm bitumen and concrete for basking. Types of vegetation reportedly consumed include figs, lilly-pilly fruits, berries, and other fruits and flowers.