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samsun
at Wed Sep 28 14:52:12 2005 [ Email Message ] [ Show All Posts by samsun ]
I thought this was interesting...
INTRODUCTION The Short Tailed Pygmy Monitor (Varanus brevicauda) is the smallest monitor species in the world (Wilson & Knowles, 1988; Ehmann, 1992; Bennett, 1995; De Lisle, 1996). They occur throughout central Australia from the coast of Western Australia through to the interior of Northern Territory and north western South Australia to western Queensland. They occur in compacted sandy loam often associated with gravel, in areas dominated by spinifex (Triodia sp.). This terrestrial species is secretive, rarely seen active above ground, and is mainly encountered by digging up burrows or, more commonly, through the use of pit traps (Pianka, 1994; James, 1996). Much of the published data on the ecology of this species is based on the Minilya Roadhouse in Western Australia. This was towards the end of the summer wet season and, three weeks prior to this observation, this part of the coast of Western Australia was hit hard by Cyclone Steve.
OBSERVATION Whilst stopped on the road next to a flooded water crossing, I noticed a small animal in the water. Closer inspection confirmed that it was a small monitor in the slow moving current. On first appearance the posture of this specimen led me to believe that it was actually drowned, half-floating. However, while leaning out over the animal and without disturbing the water I realized that it was in fact very much alive. The eyes were closed and the front legs were tucked in straight down beside the body. The tail and hind legs were still in a burrow in the ground. Its entire body was under water except for the snout and nostrils, which were just breaking the water surface. To reach oxygen it was stretched straight up as far as it could with its belly surface leaning slightly into the current.
DISCUSSION During floods it is not uncommon to see reptiles on the move, heading for higher ground before retreat sites go under water, or having already been washed out of their refuge. Many terrestrial reptiles are adept swimmers (Jackson, pers. obs.) yet they would struggle in rapids of water caused by the more severe floods. During the above observation the rain had begun around 8:00 pm the night before and rained heavy until around 4:00 am in the morning. There was already a lot of water around due to all the previous rain. I believe that this specimen of V. brevicauda more than likely spent the night submerged. By the time the observation was made the sun had been out for a few hours. The presence of the sun may have drawn the monitor to the surface of the water for air during what is their normal active time of day. Whilst the need for oxygen required the lizard to surface despite the presence of a water current, it anchored itself to its burrow rather than opting to swim to a shrub or dry ground. When reaching down and grabbing the monitor for closer inspection it immediately tried to pull itself back down into its burrow, exemplifying its ability to retreat into its flooded burrow if required. Leaving the burrow for higher ground could have left the monitor exposed to predation for a prolonged period until alternative shelter could be located, thus resulting in the development of this unique defense strategy. ----- I can picture in my mind a world without war, a world without hate. And I can picture us attacking that world, because they'd never expect it.
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- Article by Richard Jackson, Australia Zoo - V. brevicauda observation - samsun, Wed Sep 28 14:52:12 2005
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