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Monogamous Shingleback Lizard

Shingleback lizard

A Beauty of the Desert Whose Relationships Outlast most human efforts

The Shingleback lizard, also known by its scientific name Tiliqua rugosa, is a fascinating and unique species found in Australia. Other common names used in various states include bobtail, shingleback, two-headed skink, stumpy-tailed skink, bogeye or boggi, and pinecone lizard. Rugosa is referred to as yoorn by the Noongar Aboriginal people.

Tiliqua rugosa is currently classified into four subspecies:

Tiliqua rugosa asper: eastern shingleback – Australia’s east coast
T. rugosa rugosa: Western shingleback or bobtail – Western Australia
Rottnest Island bobtail or Rottnest Island shingleback (T. rugosa konowi) – Rottnest Island, Western Australia
T. rugosa palarra: Shark Bay shingleback or northern bobtail – Shark Bay, Western Australia

With its distinctive shingle-like scales and calm, gentle disposition, the Shingleback lizard has long captured the attention and admiration of people around the world.

Physical characteristics of the Shingleback lizard include its medium size, It has a short, wide, stumpy tail that looks like its head and may be used to confuse predators. The tail also contains fat reserves, which are used during brumation in the winter, when many lizards perform a behaviour similar to hibernation except they need water every day but can go without food. This skink is an omnivore, eating snails and plants and spending much of its time searching for food in the vegetation. It is frequently seen basking on roadsides or other paved areas in human habitation.

Tiliqua rugosa has a heavily armoured body and comes in a range of colours from dark brown to cream. It has a snout-vent length ranging from 260 to 310 mm (10 to 12 in) and a large body for its length. Their eyes are small and reddish-brown to grey in colour.

It has a triangular head and a bright blue tongue that is hidden inside a bright pink mouth and its short, stumpy tail is shaped similarly to its head. This is probably a defence mechanism to confuse predators although it also stores fat and has led to the common name of “two-headed skink”. Shinglebacks, unlike many other types of skinks, this one cannot shed its stumpy tail.

The average lifespan of these skinks is 10 to 15 years, but some individuals have been known to live in the wild for up to 50 years. Normally, the species sheds their skin in its entirety, including the eye covering. This can take several hours, during which the lizard rubs against various objects to aid in the process.

Habitat

The Shingleback lizard is found in a variety of habitats across Western Australia arid country, including eucalypt forests, grasslands, and deserts. It is a mostly sedentary species, preferring to spend most of its time basking in the sun or seeking shelter in a burrow or other protected area.

Despite its tough exterior, the Shingleback lizard is actually quite gentle and docile by nature. It is a herbivorous species, feeding on a variety of plants and fruit. The Shingleback lizard is also known for its slow and methodical movements, as well as its tendency to form strong bonds with its mate.

Reproduction

The species has sexual dimorphism, with males being stockier and having a larger head than females, though females generally grow larger than males.

Sexual dimorphism refers to the physical differences between males and females of the same species. These differences can be subtle or pronounced, and can involve a wide range of physical characteristics such as size, shape, color, and behavior.

Sexual dimorphism is thought to have evolved in many species as a way to enhance the chances of successful reproduction. For example, the bright colors and elaborate courtship displays of male birds may help to attract females and increase the chances of mating.

Unlike most other lizards, its young are born alive rather than hatching from eggs. Females can have a single offspring that is 35% of her body weight on average. Brood size can range between one and four relatively large offspring. The trade-off with small litter size versus large body size increases their survival chances. Females have a well-developed placenta through which they feed their young the after birth.

Unlike most other lizards, this species is monogamous and re-unites in pairs from September to November prior to breeding season. For up to 20 years, couples have been known to return to each other every year. The breeding season lasts from December to April, with a gestation period of 3-5 months.

The young consume their afterbirth as soon as they are born. They remain in close proximity to their parents for several months before becoming independent, forming a colony of related skinks.

While parenting, the male of a monogamous couple eats less while remaining alert and ready to give an alarm. He will follow the female to protect her from rival males while she feeds and cares for their offspring. These skinks have been observed grieving or brooding for their pair partner when one of the pair is killed.

Diet

It is an omnivorous creature that feeds on snails, insects, carrion, vegetation, and flowers. They eat other slow-moving species because they are slow. This could explain why T. rugosa prefers plants more than other blue-tongue skink species. With their powerful jaws, they can easily crush snail shells.

They have been observed eating human food, such as sausage and chicken, as well as fruits such as strawberries, bananas, and passionfruit, due to their proximity to human habitation and settlement.

Threats

Dingoes, Australian pythons like Morelia spilota, and local indigenous people used to prey on the species; today, large, introduced feral species like foxes and cats are more likely to pose a threat. Birds of prey such as falcons and kookaburras, as well as large snakes, prey on these skinks in Western Australia’s bush habitat.

Ticks and nematodes frequently parasitize this species by attaching themselves under scales or in the ear. Ornithodoros gurneyi, a kangaroo soft tick, has been studied as a common parasite, with claims that it infects the skinks when they spend time under trees or shrubs, where they commonly seek refuge during hot summer days.

Conservation status

While the Shingleback lizard is facing a number of threats to its survival. Habitat loss and degradation, the pet trade, and feral species are among the most significant threats to this species. As the human population in Australia continues to grow, the natural habitats of the Shingleback lizard are increasingly being encroached upon.

In particular the subspecies T. r. konowi, located on Rottnest island, is considered Vulnerable. Conservation organizations and government agencies are working to protect and conserve this species, through efforts such as habitat restoration and raising awareness about the importance of the Shingleback lizard and the threats it faces, we can help to ensure that this incredible species continues to thrive for generations to come.

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