- Written by Nadia O’Carroll
The Blue-tongue, as its commonly known, may grow to 60 cms in length, its head is broad and triangular, its body is stocky and its tail is short and tapered. Its legs are also short with five fingers and toes. The body is brown to silver grey, barred by dark bands; body scales are smooth and shiny. The most famous feature, is its bright blue tongue, which contrasts dramatically with its pink mouth.
This lizard is diurnal and forages on the ground for slow moving prey such as snails, slugs, caterpillars and beetles as well as consuming some plant material. Blue-tongues are a very effective form of natural pest control, but any use of snail and slug bait will poison and kill them.
As temperatures decrease in autumn, the Blue-tongue becomes increasingly sluggish; eventually it reaches a state of dormancy called brumation and remains buried in soil and leaf litter until warmer weather arrives in spring.
Blue-tongues are usually solitary except in the mating season, September to November, when males wander in search of females. The females give birth to large litters (up to 25) of live, fully formed, independent young in late January. Blue-tongues probably reach maturity when they are 3 years old, they can be long lived and may survive 30 years.
Blue-tongues show strong fidelity to their territories. Females are more sedentary than the male and have a far smaller home base, much of their time is spent in core shelter sites, and they use corridors of vegetation to move between these havens. Males have larger territories, in one day an urban male Blue-tongue was tracked visiting 15 backyards.
By flicking its tongue the Blue-tongue is able to collect important chemical information about its environment, prey, territory, threats and other lizards. It also employs chemical signals itself in a variety of social, feeding and other behaviours.
A Blue-tongue under threat has very little defence – it bluffs by flattening its body, opening its mouth to show its blue tongue and hissing. Another strategy is to drop its tail as a means of distracting a predator.
There are measures you can take to make your garden Blue-tongue friendly. Plant some low shrubs and leave rocks particularly along fences; do not use snail, slug bait and other toxic chemicals; restrain cats and dogs from harassing or attacking lizards; do a quick check of lawns before mowing or whipper-snipping; (unfortunately Blue-tongues tend to hide from mowers rather than running away).
Blue-tongues do not like being handled, if you have to catch or move one, gently wrap it in a towel and support its body when lifting it.
Scientists are concerned that urban Blue-tongue numbers are falling, hardly surprising in view of all the threats they must face every day.