Nesting, egg incubation and hatching by the Heath Monitor Varanus rosenbergi in a termite mound
Year: 1991
Type: article
Abstract: Aspects of at least three nestings by the Heath Monitor in a termite mound near Sydney were observed between 1988 and early 1991.A system was developed to measure temperature, carbon dioxide (CO2) and humidity in the vicinity of the eggs, and also to provide early warning of the hatching.The female(s) dug narrow nesting burrows through the upper side of the termite nest (where its compacted zone is weakest) into the flaky deep core of the mound.Between three and four eggs were laid each time and these were partly covered with soil by the female(s).The termites entombed the eggs in the mound's core where temperatures remained in the range of 33.3 to 38.6°C all year.The parent(s) remained in the vicinity of the mound for 2 to 3 weeks, possibly to protect the nest.Development was complete within five months of oviposition at which time one embryo was tightly compacted within the entombed egg.Carbo dioxide levels were high (9670 to 14000°microlitres/ millilitre) as was humidity (never below 92%).Not one of the three laid clutches (9 eggs) emerged as hatchlings; in each case the embryos died within their egg cases.It is concluded that the hatchling monitors are probably liberated by a nesting female or a tending parent.The wide variation in hatching times published for some Australian reptile eggs may be due to the retarding effect of high COzlow O2 concentrations.The effect of altered CO2O2 concentrations in large egg masses on hatching times is outlined.
Source: Herpetofauna
DOI: 10.5962/p.420514
Authors: Harald Ehmann, Gerry Swan, Geoff Swan, Brendan Smith
Institution: University of Technology Sydney
Language: English
Domain: Life Sciences
Open Access status: hybrid
OpenAlex ID: W4410137528