06 July 2008

Southern Heath Monitor - Varanus rosenbergi

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Southern Heath Monitor - Varanus rosenbergi

A medium sized goanna growing to 130 cm in length (4' 3'), which strolls with an arrogant swagger around the bush and granite outcrops in search of bird eggs or any animal (dead or alive) that can be caught and consumed. It is the only monitor lizard in the southern area, so you cannot confuse it with others, although the Gould's Sand Monitor may be found a little further north in the mallee region.
Unfortunately this goanna is far from being common in the Esperance region and more often their tracks are all that is seen as they travel around. I spend most of my time in the bush and only encounter one to three animals a year. I suspect their lack of numbers is related to cat and fox predation when young and probably of baits set for foxes near agricultural areas.

Update 3/12/2009 (Photos added)
Since the original post (nearly 18 months ago), which contained no photographs, I have been very keen to acquire some and although several monitors have since been seen, they have all disappeared into the bush before I could get close enough. One time I actually saw three goannas over a couple of hundred metres that were probably tracking the same dead animal, but they all swiftly headed back the way they had came once they sighted me.

However, within the space of a month I have encountered two mature Southern Heath Monitors that were approachable. The first was 55 km, or 34 miles west of Esperance (five of the photos above), it had just come out of the low shrubby heath into a slashed firebreak and made it very clear to me and my Jack Russell Terrier that it was not going to move and stubbornly stood its ground. It inflated itself and separately arched its back, neck and tail. It then uttered a series of deep guttural hisses. My dog wisely gave this aggressive goanna a big miss and quietly sat some distance away whilst I took some photographs, and not once did the goanna take a backward step or attempt to retreat.

The second Southern Heath Monitor was encountered about 35 km or 22 miles east of Esperance and had just wandered out of the bush (heath) onto a little used track/firebreak. I had not been seen and it was slowly, but purposely walking away from me, however when I got to within 6 metres, it did spot me, then stopped and gradually turned side-on to display its threat pose (two photos above). As I continued closer, it nonchalantly turned into the bush besides the track and after a short eye to eye stand-off (to let me know how tough it was), it slowly ambled off.

Both animals were mature and close to their maximum size of 1.3 metres, or a little over 4' in length. They had very strong muscular bodies (see close-up of rear leg) and were in their prime, plus emboldened by their top predator status, thought they deserved a good measure of respect, which I might add they got.

Monitors have a long deeply forked tongue (see photo above) from which they taste/scent what is on the wind. It is a very sensitive organ with little missed, and if the breeze is from the right direction, even birds nests high in trees can be located. Australia has by far the largest number of monitor species including the large Perentie, Varanus giganteus that can grow to around 2.5 metres (over 8') in length. I have seen a number of these super lizards whilst prospecting in the mid-north of Western Australia, where they were sheltering in caves and under huge house sized boulders that had fallen away from a cliff. It was also the place (going on the skeletal remains) that feral goats came to die, which no doubt was an added bonus. Goannas big or small are very impressive animals.