Shinglebacks – Victoria’s special rural lizard

Other names

Stumpy-tailed Lizard, Bobtail (WA), Sleepy Lizard, Boggi (NSW).

Introduction

The fantastic-looking shingleback lizard is a wonderfully unique-looking lizard, with its large overlapping scales, broad triangular head and obnoxious stump-ended tail. It has a distinctive threat display with its dark cobalt-purple fleshy tongue. Once you get up close, you only have to look into those dark eyes and see an intelligent gaze looking out to know there is something special about them.

Shinglebacks are a rural success story, commonly seen all over the landscapes of south-eastern and south-western Australia. They have an omnivorous diet, but mostly eat vegetation, especially introduced weeds. They have learnt to survive in open ranges in areas where the temperatures on the ground can get over 50 degrees. In southern areas, the winter temperatures may get as low as 2 degrees, even lower on the ground. So the lizard has to be adaptable and rugged.

Home range

The shingleback forages over a home range of around 2–8 hectares. The biggest movements are in spring, when they roam in search of their mates; males reportedly are the biggest roamers. Females tend to have a smaller home range. The lizards may often be seen crossing roads, repeatedly back and forth. You may move the lizard off the road only to see it come back again, sometimes over a few days.

Roads will be part of its home range and are also a great temperature regulator, with a good surface temperature, like a heat pad. The warmth radiates upwards, assisting digestion of food and keeping the lizard at its preferred temperature. Roads often have a source of food all over them, from other dead animals to insects that have been knocked out by traffic. This also gets them into trouble with cars; roadkills are a common sight in the areas where they are common.

Shinglebacks are also seen with a grieving partner alongside. Males in particular tend to stay with their deceased mate for a period of time. When foraging, these lizards will shuttle from one bush to another, every once in a while feeding on native shrubs, seeds, leaves, stems or dropped berries. At rest, the lizards will remain out of sight under dense low shrubs, in a dense clump of grass, under discarded rubbish, even under spinifex grass tussocks. During winter, they will often go right into leaf litter under dense ground cover.

Male shinglebacks roam widely but, once paired in spring, will remain with the female, guarding her from other males. They will fight for the chance to mate and often can get serious mouth wounds from a rival. When fighting, males often grasp each other by biting; two lizards will often grab each other in their mouths and cause injuries, even fractures of the jaw. This would later seriously diminish their chance of beating a rival the following year.

Males remain with females from several days to several weeks. Mating is usually done under cover, out of view, due to predation risks. They will forage together and, as many drivers can attest, a common sight in spring, October through to November, is a pair of shinglebacks moving along together around the roads.

During summer, the lizards reduce their home ranges and are typically rarely seen around the roadside. Both male and female will be feeding around the summer retreat site and only come out during the early morning, when the heat is at its lowest. The female, with her growing live young, will bask to increase thermal energy for reproductive purposes and is often seen in late summer, just before parturition.

In late summer, after giving birth, the female will have one to three young following her and shows some maternal interest in her young for a week or so. She then will leave them to search for her winter site and forage around until the weather pattern indicates dormancy.

Juvenile lizards will remain with their mother initially, but will move on after a week or so. They are very vulnerable to predation, especially by raptors and brown snakes. The skin is quite soft in younger lizards, and large-bodied brown snakes will feed on them. They make substantial and easier prey in the drier periods of the month, when other food may be harder to get.

They will feed like their parents and, over the next few years, mature to become adults within 3 years, but females likely will not breed until their 4th or 5th year.

Boy vs Girl

Sexing the lizards, while subtle, can be done visually. Males have a thinner, tapered tail, and females have a shorter but much wider, thicker tail. The male can be sexed manually by inverting a hemipenis; this is easier when they are warm, and usually easier in wild-caught individuals than in captive animals.

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  Shingleback lizard on sandy ground in the Little Desert.

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  Shingleback on a road near Murrayville, Victoria.

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  Shingleback sheltered beneath leaf litter and branches.