Southern Africa's Largest Lizard

By Bruce G. Marcot, Ecology Picture of the Week:

Behold the behemoth of Africa!  This is southern Africa's largest lizard, a water monitor.  

Water monitors belong to the same family as goannas in Australia and the infamous Komodo dragon, the world's largest lizard, of Indonesia.  

Water monitors can grow to 120-160 cm (4-5.2 feet) long.  Like other members of family Varanidae, they have the typically long, flexible neck, strong claws, long tail, and narrow head. 

They swim well, and often take to water if disturbed.  I recall one incident when I was on foot exploring the densely overgrown banks of the Zambezi River in Victoria Falls National Park of northwestern Zimbabwe, when I accidentally spooked a water monitor laying hidden in the vegetation.  In an instant, the lizard, just a few feet from me, suddenly arched its back, reared up on its hind legs and tail, and spun around and plunged back into the river.  I continued my exploration after my heart returned to my chest! 

Water monitors are usually shy creatures, but they will bite hard if cornered or captured.  Adults eat crabs and other aquatic creatures, and the young eat mostly insects and small frogs.  They lay eggs within active termite nests which likely provide protection from other predators and temperature changes.  

Did you know that water monitors have been introduced to south Florida as escapees or pet releases?  This might not be good news for the scarce, native American, crocodile that also resides there.  

 --Bruce G. Marcot

Image and text © Bruce G. Marcot, Ph.D. Research Wildlife Ecologist,
who produces the Ecology Picture of the Week website.