Influence of temperature and moisture on eggs and embryos of the white-throated savanna monitor Varanus albigularis: implications for conservation

Published source details Phillips J.A. & Packard G.C. (1994) Influence of temperature and moisture on eggs and embryos of the white-throated savanna monitor Varanus albigularis: implications for conservation. Biological Conservation, 69, 131-136.
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This study is summarised as evidence for the following.

	Action	Category
	Relocate nests/eggs for artificial incubation: Lizards Action Link

Relocate nests/eggs for artificial incubation: Lizards

A replicated, controlled study in 1990 in dry savanna in north-central Namibia (Phillips & Packard 1994) found that artificially incubated white-throated savanna monitor Varanus albigularis egg hatching success was almost double that of natural nests, although hatchlings were similar sized. Overall hatching success of artificially incubated savanna monitor eggs was 81% (120 of 148 eggs) compared to 47% (50 of 107 eggs) for natural nests (results not statistically tested). The average length of artificially incubated hatchlings was similar (115 mm) to hatchlings from natural nests (114 mm; results not statistically tested). Incubation time was longer and hatchlings were larger at lower incubation temperatures and in moister conditions (see original paper for details). In 1990, nine female monitors were radio-tracked through the breeding season. Five females were brought into captivity to lay eggs and four were monitored laying eggs in the wild. Captive-laid eggs were collected and incubated in mixed clutches in 27 boxes containing moistened vermiculite (15–17 eggs/box). Nine boxes contained high (-150 kPa), medium (-550 kPa), or low (-110 kPa) moisture levels. Three boxes of each moisture level were incubated at 27, 29 or 31°C. Artificially incubated (from 148 eggs) and natural-nest hatchlings (from 107 eggs) were checked and weighed on emergence.

(Summarised by: Katie Sainsbury)