their review of the Ctenotus uber orientalis
complex (Storr, 1971),
Hutchinson and Donnellan
(1999) recently elevated orientalis to full species
status. In relation to the diet of Ctenotus;
Greer (1989), citing other references, stated; “Ctenotus
appear to be opportunistic predators, although some species are known
to take more than 10% plant material by volume.” Ehmann (1992) wrote
that the diet of Ctenotus uber consists of
insects, spiders, centipedes and small lizards. Bennett (1997) recorded
the diet of presumably ACT populations of Ctenotus
insects and occasionally smaller skinks.
The following account provides details of an adult C. orientalis expelling a recently ingested hatchling Mallee Dragon Ctenophorus fordi.
Time: hrs (Eastern Standard Time/ Daylight Savings Time).
Weather Conditions: Fine with no cloud cover and a gusting westerly breeze. Air temperature: 25.6°C, Relative humidity: 32% (Measurements taken with a Smart Digital Thermo-hygrometer).
Location: The Big Desert Wilderness area, central-western
Habitat: Pale, clay-based interdune plain between a sand dune system running paralell and aligned east-west. Mallee/heath vegetation with an upper layer comprised predominately of Callitris verrucosa and Eucalyptus baxteri and with a dense ground cover of small shrubs including Hakea spp. and sparse large clumps of Triodia irritans.
Notes: Whilst stalking an adult male Painted Dragon Ctenophorus pictus that had retreated into a shaded area beneath a dense stand of Callitris verrucosa, an adult C. orientalis was inadvertently flushed from the cover of a small shrub nearby. After the skink was secured by hand for photographic purposes, one of us (Chris Hay) remarked that unfortunately the lizard had been squashed, as its tongue was protruding externally. Upon closer inspection the ‘tongue’ was in fact the hind limbs and tail of a hatchling C.fordi.
The hand pressure applied when pinning the skink was sufficient to almost expel the recently ingested agamid. The hatchling dragon had been swallowed head first and was gently removed for closer scrutiny. Length and weight measurements of both lizards were taken using a set of Mitutoyo Digimatic Callipers and Mettler Digital Scales.
Snout to vent length: 55.4mm. Tail length: 87.6mm (original tail). Total length: 143.1mm. Head length: 10.8mm (taken from the anterior edge of the rostral scale to the posterior edge of the parietals). Head width: 8.0mm (at the widest point). Weight: 3.95 grams (exclusive of the prey item).
An adult Striped Skink Ctenotus orientalis from Big Billy Bore, Big Desert, western Victoria.
Snout to vent length: 26.3mm. Tail length: 19.5mm. Total length: 45.9mm (note that the posterior two thirds of the tail was missing). Head width: 6.7mm (at the widest point). Weight: 1.21 grams. The C. orientalis was subsequently released at the point of capture.
That C. orientalis is capable of consuming prey more than a third of its own body weight is noteworthy. Greer (1989), referring to the genera stated: “Not surprising, larger individuals and species are able to eat larger prey than smaller forms and hence take a greater variety of prey.” Upon closer inspection of the hatchling C. fordi it was noted that there were several tiny lacerations on top of the head consistent with bite marks. The entrails were protruding out of the cloacal opening, possibly caused by the jaw pressure applied by the C. orientalis to the trunk of the body or by human hand pressure on capture. The proximal tail stub was also closely examined and the break appeared to be very recent and may have occurred during the ensuing struggle with the skink.
Pianka’s (1969c) studies suggested that sympatric Ctenotus species minimise
competition by differing their daily and seasonal activity periods,
prey item sizes and foraging patterns. Hatchling C.
found to be abundant during our visit to the
I would like to thank the anonymous referees who took the time to review this paper and for their helpful comments and improvements to the manuscript.
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