Australian water dragons (Intellagama lesueurii) are the largest and one of the most readily recognizable dragons (family Agamidae) in Australia, males capable of growing more than a meter in length. There are two subspecies of Intellagama: I. l. lesuerii and I. l. howittii, the latter being the Gippsland water dragon. Both subspecies have an arboreal and riparian lifestyle, clambering around rocks and trees with ease using muscular limbs.
They have long and powerful tails greater than 1.5 times the length of their body, capable of generating propulsion underwater along with torque generated by undulations of the body – much like a marine iguana. In fact, they can regrow their tails if damaged, much like geckos and skinks! Tail regeneration in agamids was a huge surprise to me, and evidently tail length is an important character for fitness in this species.
Water dragons have a robust head with a nuchal crest spanning the dorsum all the way down to the tail tip. They have large jowls and tympana, almost as chunky as that of a bearded dragon (Pogona spp.). There is also a prominent black stripe behind each eye, a very attractive feature to me in animals. I’ve always thought dark facial stripes are so cool-looking such as in cheetahs and vipers, and the markings seem to be present in a plethora of taxa.
As opposed to many reptiles that become less colorful as they mature, male water dragons develop yellow and red colorations on the chest. These conspicuous colors are used in antagonistic encounters with other males, e.g. competition for space or females. However, there is no evidence the colorations are relevant to courtship behavior. Although I haven’t taken a photo of the red coloration from a good angle, I will update this blog post when I do.
Australian water dragons thrive in a variety of habitats, including human-modified ones. In some human populated areas near the coast, lizards are extremely abundant and are not shy about intraspecific interactions even when a person is standing just a meter away. Watch the video at the end of this post to see communication signals including hand-waving, head-bobbing, and wave-like tail movements! As you would expect, most behaviors featured in the video are used in intrasexual competition and dominance displays.
Like most dragons, water dragons occupy habitats where there are areas of direct exposure to sunlight for basking, usually with adjacent underbrush to escape from predators. They are omnivorous and have a diverse diet, including all kinds of insects, arachnids, and crustaceans, and vegetation and fruits. It is unlikely that water dragons actually forage underwater, but they are capable of diving and staying submerged for up to one hour.