Blue-tongued lizards are on the move at this time of year, so here's a few things you should know

Extract from ABC News 

ABC Radio Hobart

By Georgie Burgess

Updated yesterday at 11:09am

Photo: The lizards are a common site in backyards. (Supplied: David Maynard)

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As the days get longer and warmer, it's not just humans that are drawn out into the sunshine.

Blue-tongued lizards are out and about, and it's often hard to tell if they are fighting or mating.
The lizards are a common sight in backyards across south-eastern Australia, but they have some traits you may not be aware of.
Blue tongues, or blotched lizards, are also the subject of a number of myths when it comes to their bite and interaction with snakes.
Dr Ashley Edwards from the University of Tasmania has studied the lizards for 24 years, and said the males started emerging from hibernation in September — with attitude.
"They start getting all worked up. They fight with each other through October and start mating in November," she said.

"When you come across two lizards together it's sometimes hard to tell whether their intentions are honourable or if they are fending off another male."

Photo: The mating ritual can be a vigorous process. (Supplied: Sharon Smith)

Why the blue tongue?

Experts still don't really know why the lizard has a bright blue tongue, but Dr Edwards ruled out a link to their diet.
All around the tongue is pink, and only the tip is blue.
Dr Edwards said it was likely designed as an intimidation measure.

"When you see them using their tongue it's part of a threat display.

"If they open their mouth and hiss at you, or go sideways to make themselves look bigger and puff up their ribs and open their mouth and flash that brilliant blue tongue inside a pink mouth, it makes a really good contrast and it's quite startling.
"If you were another boy you'd be put off by that, and if you're a predator it might startle you."

Infographic: It's believed the blue tongue is meant to help intimidate predators or rivals. (ABC Open contributor michelle_j_photography)

Live young

Unlike many of their reptilian cousins, blue-tongued lizards give birth to live young.
Dr Edwards said this was common for reptiles in Tasmania and south-eastern Australia.

"Because it's so cold here, if you lay eggs and put them in the ground to develop and it's cold, they may not hatch.

"If you keep your babies inside, you've got much greater control of where you lie in the sun and you can make sure your babies are at the right temperature to grow."
She said the most offspring she'd seen in one birthing was 17.
"They just kept coming out."
Blue tongues are common in backyards, and Dr Edwards said they'd coped well with urbanisation.

Photo: Blue-tongued lizards give birth to live young. (Supplied: Ashley Edwards)

How to be a good host

If you're lucky enough to have a resident blue tongue, there are a few things you can do to help accommodate them in your garden.
Dogs can kill them, so it's helpful if there's rocks or bushes for the lizards to scuttle away to and hide in.
Snail bait can also be harmful — the lizards won't eat the bait but they will eat the poisoned snails.
Dr Edwards' advice is to skip the bait, and let the lizards take care of the snail for you.
"If you've got a blue-tongued lizard in your garden, you probably won't have much in the way of snails," Dr Edwards said.
Netting and wire to protect fruit trees or poultry can also be deadly for the lizards.
"They can crawl through netting if it's too small, but then they can't back out because of the direction of their scales and they can die if they get stuck out in the sun."

Busting myths

One common belief is that if you have blue-tongued lizards in your garden, you won't get snakes.
Dr Edwards said she had never come across any evidence to support the claim.
"I have seen snakes and blue tongues in the wild living in exactly the same places. They respond to exactly the same environmental cues.

"I can't think of a single physiological or ecological reason they wouldn't be able to co-exist happily."

Photo: There's a few things you can do to help accommodate blue tongues in your garden. (Supplied: Ashley Edwards )

Another tale is that if the lizard bites you, the wounds will reappear on the anniversary of the bite or every six years.
Again, Dr Edwards said the tale was baseless but might have come from stories about goannas, which blue tongues are sometimes colloquially known.
"I know people who have been bitten by a blue-tongued lizard and they haven't had the wound reappear.
"When goannas bite they have nasty saliva and even venom.
"I know people who have been bitten where infections have gone down into the bone and come back up later."
Blue tongues, however, have an extremely strong jaw.
"They have to be able to get through snail shells and fight other males," Dr Edwards said.
When fighting, males can engage in crocodile-like death rolls which each other.