Varanus varius (SHAW 1790)
Lace Monitor
Varanus
varius belongs to the subgenera Varanus. The major coloration
on top is a deep blue with numerous scattered white, cream-colored or yellow
singles scale. Some of these scales form groups and greater spots or areas.
In young animals these bright areas are ordered between darker areas but
this pattern of crossbands fades in age. In some animals alternately black
and yellow ribbons appear on the body, the tail and on the limbs (belli-phase).
This banded phase occur in an area of the northern New South Wales and the
adjacent southern Queensland.
Normaly there are black bands seen across the snout, the chin and the throat.
The tail is marked with irregular yellow crossbands. The head scales are
moderate large and smooth, while the Supraocularia is uneven. The nostril
is situated at the side, and is approximately twice as far to the eye then
to the tip of the snout. Approximately 200 scale rows are around midbody.
A clearly visible number of extended scales, which form a comb-like stucture
is ordered on the inside of the base of the fourth toe. The tail is squeezed
together strongly at the side unless at the base with a clearly visible
double keel on the top side. It is approximately 1.8 times as long as SVL.
The average total length is 150 cm but also animals which grew longer than
200 cm are described.
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The
distribution of Varanus varius extends from the Cape York Peninsula
in northern Queensland along the east coast of Australia to Victoria in
the south. This monitor species also occurs in the southeastern South Australia
(MERTENS 1942d, 1958, KEAST 1959, WORRELL 1966, BUSTARD 1968, SWANSON 1976, STORR 1980,
STORR et al. 1983b, WILSON & KNOWLES 1988, HOSER 1989, COGGER 1992, EHMANN 1992).
In the wild, the Lace Monitor normally lives on trees. HORN (1980) however reported during his study, that this monitor frequently searches
for food on the ground. According to his size carrion also is part of its
food source (KENNERSON 1980, WARD & CARTER 1988). V. varius occasionally also
feeds on bats (MANSERGH & HUXLEY 1985) and young birds, e.g. Tawny Froggmouth (KINGSTON 1980).
In the wild the Lace monitor drops its eggs in termite mounts. After the termites have repaired her damaged mount again the eggs then have both, perfect incubation conditions (temperature and humidity) and the protection from eating enemies. A very interesting breeding biology is that at the end of incubation period the female returns to the termite mount, opens it, and makes it possible for the hatchlings to ermerge from the termite mount (BARTON 1991).
Because Lace Monitors are perfect tree climbers, you have to offer the animals an enclosure with the possibility to. Therefore some stable, vertical or horizontal tree-trunks are part of the basic furnishing. HORN (1991) used as ground cover a mixture of earth, peat moss, and gravel. Since V. varius is also a very good dugger, the layer of soil should should be fairly deep. An occasional humidification of the substrate for increasing the humidity has to be recommended. Because the distribution area of the Lace Monitor reaches from the tropical north of Queensland to the mediterranean climate of Victoria, the animals can accept a big variety of different climates. Unfortunately, in most of the time you do not know from which locality and from which climatic zone your animals originate. HORN (1980) gives a good summary of some of these parameters and of the biology of V. varius in the wild.
Till now, captive breeding of Varanus varius have been described already repeatedly. The most frequent successful breedings happened in Australia, where the animals were housed under free conditions (BREDL & SCHWANER 1983). HORN (1991) reported the first successful breeding outside Australia. The female dropped two clutches of eggs with 5 or 7 eggs respectively, always 4 weeks after observed matings, in a wooden egg-laying box. The eggs were incubated in a special incubator (Motorbrueter) without substrate in a steam saturated atmosphere (BROER & HORN 1985). At a temperature of 29°C altogether 11 young animals hatched after 226-243 days. The offspring measured between 32.7 and 37.2 cm and weighed between 28.4 and 40.8 g. The rearing of the babies did not cause any problems. They grew well at feeding with fresh born mice.
VISSER (1996) reported on a further captive husbandry with the offspring of the HORN-animals at the Zoo of Rotterdam. This is therefore the first captive husbandry in the second generation of this monitor outside Australia.
A special success is reported by KRAUSS &HORN (2004). From on egg 3 offspring hatched. All babies survived and developed well. Only the body mass was a little bit lighter than in the other "regular" hatched siblings.
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