The Eastern Water Dragon (Physignathus lesuerii) is a member of the Agamidae, or dragon family and can be found throughout eastern and southern Australia, with some close relatives also occurring in the west.
As its name implies, the eastern water dragon requires a waterside habitat, whether it be the banks of a freshwater creek or river or a brackish coastal mangrove.
The lizard’s body is some 20cm (8″) long and its tail up to 50cm (1’8″) in length. However, the longest specimen on record stretched an impressive 120cm (4′) from nose to tail. The eastern water dragon is a greenish-brown to greenish-grey colour with pale yellow bands. Many males show more vivid colours during the breeding season.
Characteristics & territorial behaviour
One of the most striking features of this creature’s behaviour is its elaborate, almost prehistoric, duelling for territory. The dragon is an agile creature and is very at home in the water. They will quite effortlessly drop from a tree branch into the water if disturbed, and are very quick runners as well as remarkable climbers.
The lizards live in harem-like groups with the male controlling as many as ten (or more) females. The females are sociable creatures, sunbathing together throughout the afternoon while the male guards his territory.
Head bobbing is the most common means of communication; it can take several forms. Males bob their heads to keep their harems in order and herd the females together. Any other intruding or marauding male is greeted with a series of warning signals, including head bobbing and arching of the tail. The intruder responds in a similar manner. Throat pouches are inflated to increase apparent size and a highly ritualised struggle then ensues, jaw to jaw.
Fortunately, this fight is somewhat akin to television wrestling. Most of it is bluff and the wounds are usually superficial, with the vanquished males left to fight another day. And to the victor, the spoils – a harem, food, water, shelter and a place in the sun.
Surprisingly, the larger-than-life battle seen on “Burke’s Backyard” occurred in the Sydney suburb of Frenchs Forest, only 15km (9 miles) from the city. Which goes to show that just because you live in the suburbs doesn’t mean you can’t witness some of nature’s more primeval displays.