EPOW - Ecology Picture of the Week

The Monitor of Umbrawarra

Mertens' Water Monitor (Varanus mertensi), Family Varanidae
Umbrawarra Gorge Nature Park, Northern Territory, Australia

Explanation:  Beware the dragon of the gorge!  This is a spectacular example of an adult Mertens' water monitor lizard, a largely aquatic denizen of the tropics of north central Australia.

After a hot hike into uninhabited Umbrawarra Gorge Nature Park in Northern Territory, my mates and I spied this unwary reptile sunning itself along the creek. The Gorge is accessible -- by humans, anyhow -- only during the dry season, and even then only by rock-hopping or wading.  

Note the laterally compressed tail, adapted for strong
and swift swimming.  These lizards typically inhabit
rivers, pools, and billabongs (swamps and wetlands).

Mertens' water monitors are active predators, locating their prey of fish, frogs, crabs, and insects by sight and smell.  The species is not threatened, and its presence can serve as an indicator of healthy aquatic, wetland, and riparian ecosystems.

Traditionally occupied by the Wagiman Aboriginal people, Umbrawarra Gorge was also the site of a tin mine in the early 20th century.  

Information:
     Mayes, P.J.  2006.  The ecology and behavior of Varanus mertensi (Reptilia: Varanidae).  Ph.D. Dissertation, Edith Crowan University, Western Australia. 249 pp.
     Swan, G. 1997. A photographic guide to snakes & other reptiles of Australia. New Holland Publishers, London. 144 pp.