Secretive yakka skinks battling predators, habitat loss while on the brink in outback Queensland

Stephen Peck with an endangered yakka skink. (ABC Western Qld: Danielle Lancaster)

Stephen Peck's eyes light up when you say the word "yakka". 

Mention the unusual name ER 181, and his smile widens as his dark brown eyes become considerably brighter.

ER 181 is Mr Peck's favourite. 

"It's a love affair like no other," he says.

"It's not the sexiest name. ER refers to the species, Egernia rugosa, and I first recorded her in January 2009, but for me, she is the cutest and sexiest reptile in the world."

A PhD candidate at the University of Southern Queensland, Mr Peck has been studying the endangered yakka skink in the mulga lands surrounding Charleville in western Queensland since 2008.

For the past 14 years, he has monitored up to 40 sites within a favourite habitat of the yakka.

Mulga and brigalow provide perfect conditions for the research sites to establish vital information on the rare yakka.   (ABC Western Qld: Danielle Lancaster)

The skinks are meticulously measured, photographed, weighed and the information placed into detailed profile books by Mr Peck.

For this remarkable member of the lizard family, this critical information is building a database to save yet another endangered Australian reptile.

Mr Peck measures the snout length of a yakka. (ABC Western Qld: Danielle Lancaster)

Yakkas are different

Yakkas are not like many other reptiles.

They live in family groups, have a communal scat pile, and on each yakka's creamy throat are black spots, with no two skinks having the same markings.

The markings on the yakka’s throat are a way to identify each animal with no two being the same. (ABC Western Qld: Danielle Lancaster)

Yakka skinks can have two eye colours — red or brown — but the reason for the unusual trait remains unclear.

"I wish it could be as easy as sexual dimorphism, but unfortunately, it's not," Mr Peck said, referring to the condition where a species' gender determines whether it has a specific attribute.

Red and brown eye colourings are one of the many differences yakka skinks have with other lizards.   (ABC Western Qld: Danielle Lancaster)

The docile lizards are perfectly camouflaged for their chosen environment.

Colourings range from pale to dark brown, suiting the soil colouring, leaf litter, and general surroundings.

The yakkas' distinct markings suit their environment.   (ABC Western Qld: Danielle Lancaster)

Growing up to 40 centimetres in length, these are not tiny garden skinks — they are around the size of a blue-tongued lizard.

The yakka shares two characteristics with all skinks: it stores energy, or fat, in its tail and has the ability to drop the tail when threatened, before it heals and regrows.

Yakkas drop their tail as a defence mechanism developed over millions of years to distract predators. (ABC Western Qld: Danielle Lancaster)

Why are yakkas threatened?

Yakkas are thought to live up to 30 years of age and are "site-dependent, which means if the site gets disturbed, they won't move on," Mr Peck said.

ER 181, Mr Peck's love, he estimates, could be 19 years of age after first recording her in January 2009.

"They love an old pile of logs, abandoned rabbit warrens, and I often hear stories of landholders saying they have this big lizard living under their shearing shed."

There are a number of causes for the yakka's decline, which has seen it become listed as vulnerable.

While habitat loss is a significant factor, predation by foxes and feral cats plays near the top of the list.

"Cats and foxes have an acute sense of smell, and the yakkas are creatures of habit. The smell of the communal latrine attracts feral predators who learn quickly to wait and pounce."

Mr Peck said he sees the impacts of the feral animals regularly, both in tracks around his sites and on night-vision cameras.

A feral cat is photographed hunting a yakka on a camera. (Supplied: Stephen Peck)

The future for the yakka

As the yakkas bask in the sun, hanging on to the last few fragments of brigalow and mulga for survival in outback Queensland, Mr Peck strikes a positive note.

"It's been a crazy growth season, with some measuring up to 20 millimetres longer than usual growth patterns," he said.

Mr Peck says, as more people are educated and informed on how to recognise and protect the "sexy" reptile, there is always hope.

A yakka in the mulga lands near Charleville in western Queensland. (ABC Western Qld: Danielle Lancaster)