These pygmy blue-tongues are facing extinction. A controversial idea may save them and other species (2024)

A lizard thought extinct for more than 30 years is currently enjoying a second shot at life in a undisclosed location outside of Adelaide.

But without a helping hand, the pocket-sized reptile may be lost again — this time for good.

Pygmy blue-tongue lizards (Tiliqua adelaidensis) were only found in a few areas in the middle of South Australia.


But with climate change turning up the heat in their original habitat and likely making it unliveable within the next few decades, researchers set up new sites in higher latitudes to see if pygmies can survive in those new environments.

Known as "climate change translocation", the practice has its critics, but if successful, it may provide a blueprint for other at-risk organisms.

One of the people most invested in their survival is researcher Dee Trewartha.

Nine years ago, Ms Trewartha stumbled into the world of the pygmy, and today, she loves the tiny South Australian creatures more than ever.

"They're really charismatic and adorable," she says.

These pygmy blue-tongues are facing extinction. A controversial idea may save them and other species (1)

As an undergraduate student studying behavioural sciences, Ms Trewartha volunteered to travel the hour out of Adelaide with some PhD students to a small field site to help catch, weigh, measure and inspect the inconspicuous creatures.

Now, while doing her own PhD at Flinders University on pygmy blue-tongues, Ms Trewartha runs the show, driving volunteers in a ute covered in blue lizard stickers out to a new second site.

On an extremely windy day, I squish into the back of the ute with a group eager to help the species survive.

Our job is to find the lizards burrows, "fish" them out using a mealworm on a string and then check how the population is faring.

Extinct or not extinct?

The pygmy blue-tongue has had an impressive history for a species that spends most of its time hiding in burrows.

It's one of a group of lizards known as Tiliqua, which are blue-tongued skinks native to Australia and surrounding islands.

The pygmy blue-tongue is one of the few species in the group that don't actually have the iconic blue tongue. Instead, it has a pink tongue in a slightly blue mouth.

The lizards grow to around 15 centimetres long, and have mottled brown skin.

With only a handful of individuals recorded, by the 1950s, it was thought that the pygmy blue-tongue lizard was extinct.

But the enigmatic reptile was simply laying low.

"[They're] hide and seek champions," Ms Trewartha jokes as we methodically scour the square plots.

"It's pretty good hiding if no-one knows you're alive."

In an extremely fateful find, in 1992, amateur herpetologist Graham Armstrong discovered a dead lizard in the belly of a road-killed brown snake north of Adelaide.

Luckily, he recognised it immediately, and called an Adelaide herpetologist to share the good news.

Researchers sprung into action, and, before long, found live specimens in the area.

It wasn't all good news though. While they had been found, there weren't many of them, so they were categorised as endangered.

They live in second-hand burrows made by spiders in native grasslands, and these are disappearing as their habitat is repurposed for agriculture.

"Spiders don't build burrows in wheat fields, so the lizards also don't live in there either," Ms Trewartha says.

These pygmy blue-tongues are facing extinction. A controversial idea may save them and other species (2)

But there's an even bigger problem looming: climate change.

How can translocation help?

In 2021, the Flinders University team released 52 lizards into a field on a private farm about 90 kilometres north of Adelaide.

This is much further south and cooler than the pygmy's traditional habitat, but the team was testing if the lizards could handle a change in climate.

Climate modelling suggests the pygmies are in danger of extinction in the next 50 years due to global warming.

"The predictions are that the temperatures will rise in the northern end of the pygmy blue-tongues' range, and we might lose populations," Ms Trewartha says.

"Translocation — moving the northern populations of lizard southwards — was decided to be the most likely way of conserving the species."

The Flinders University team has kept tabs on how the translocated lizards have fared in their new surroundings.

A study published in April this year in the journal Animal Conservation found the rehomed lizards were doing OK.

But translocation — especially in relation to climate change — is not without its critics.

These pygmy blue-tongues are facing extinction. A controversial idea may save them and other species (3)

Translocation controversy

Since a report popularised the idea of climate translocation in 2008, scientists have fiercely argued both sides of the debate.

University of Western Australia physiological ecologist Nicki Mitchell notes that some scientists are extremely excited by the possibility of moving organisms at risk because of a human-caused problem.

"But there is an equally strong pushback from ecologists who work on invasive species, saying that this is super-risky," she says.

With plenty of horror stories of species being translocated to a new habitat and then causing chaos — such as cane toads — it isn't surprising some researchers are cautious.

Dr Mitchell works with the first species in the world to be translocated due to climate change — the western swamp tortoise (Pseudemydura umbrina).

The tortoise shares plenty of similarities with the pygmy blue-tongue lizards: both reptiles were thought extinct and rediscovered, and now both are at risk of climate extinction.

But when it comes to translocation, Dr Mitchell's effort isn't the tortoise's first rodeo.

These pygmy blue-tongues are facing extinction. A controversial idea may save them and other species (4)

"Ironically, there was a captive breeding program from the zoo and they'd been releasing them 100 kilometres north of where they've been found, which is effectively the wrong direction," Dr Mitchell says.

"So, long story short, we started trials of assisted colonisation. It's the world's first example of a translocation of a threatened species motivated by climate change as the main threat."

Both the tortoise and the lizard have it a little easier when it comes to moving south than other at-risk creatures around the world. For example, they are within the same state and country, so there's less paperwork and red tape to navigate.

According to Dr Mitchell, Australia has a history of moving endangered species back to its native habitat. For example, Dirk Hartog Island in WA reintroduced 11 native species after getting rid of invasive animals.

Both Flinders and the University of Western Australia have undertaken studies showing that, in the cases of the tortoise and lizard, their new habitats were not worse off by their presence.

The day we visit the field in South Australia, there's plenty of lizards to collect, weigh, measure and then gently return home. They're doing well in their new southern habitat.

But researchers now have to come to terms with how often, and how far, they're willing to move a species to save it.

"Historically, we've translocated species everywhere. Species have been brought into Australia as crops or escaped pets," Dr Mitchell says.

"It's a really nuanced decision because you're weighing up not just the climate change threat, but also how well you can control other threats [like unintended consequences to the new habitat].

"You're never going to get it perfect. But sometimes you're going to have to make decisions quite quickly. You haven't got decades to make up your mind."

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These pygmy blue-tongues are facing extinction. A controversial idea may save them and other species (2024)


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