Bluetongues; Australia's favourite lizards

OK, so maybe that's a provocative title, but the mere fact that a large number of Australians would know immediately what you meant by bluetongue, or even just bluey, is indicative. The six Australian species of the genus Tiliqua (plus two New Guinea species) comprise the bluetongue skinks, usually referred to here just as bluetongue lizards, because they don't really seem like skinks. They are atypically large (sometimes up to 50cm long) and relatively slow, not small and slender and whisking across the surface of ground, rock or log like their numerous more familiar and ubiquitous relations.

The one exception is the Pygmy Bluetongue T. adelaidensis, barely a quarter this size; it is remarkable too in being an ambush hunter, using as cover the burrow of a wolf or trapdoor spider (having evicted and eaten the rightful owner). The story of its remarkable return from oblivion can be found here.

 

The Blotched Bluctongue T. nigrolutea (here in the high Brindabellas above Canberra) is a typical bluetongue.
It can be over 40cm long, with a heavy body and diamond-shaped head. Further south, including in Tasmania,
it can be found at sea level and the pink spots are less conspicuous.

Many Australians, even in suburbia, have a bluetongue in their yard, either as a resident or passing through. Many people leave out water or even food for them, and a very welcome tenant they are too, with a healthy appetite for snails in particular. (They do like strawberries too, but that can be managed with a bit of fencing!) The wedge-shaped face is in part due to the heavy jaw muscles which, in conjunction with large rear teeth, make easy work of crushing snail shells and beetle carapaces. 

They are daytime omnivores, with little defence against larger predators - birds of prey, goannas and large snakes, plus of course now dogs and cats. However, bluff can count for a lot, and blueys are good at it - and here's where the blue tongue comes in!

The fleshy blue tongue, which of course is just a food manipulation organ, is also utilised,
in contrast with the pink inside of the mouth, and a bit of huffing and puffing, to scare off
real or potential threats. This, in combination with the somewhat snake-shaped head, is apparently enough
to save them from at least some attacks.
This is the northern race of the familiar Eastern Bluetongue T. scincoides, which is found widely across
northern and eastern Australia.

Size apparently counts too, as they will also try to make themselves look as big as possible in such situations.

Eastern Bluetongue, Kakadu National Park.
This one has turned itself side on to me, flattened its body and tilted it towards me to appear bigger than it really is.

Unusually, the entire genus gives birth to live young. While this - which essentially means the young hatch internally - is not uncommon among lizards from colder climates, to avoid eggs developing in cold or even frozen soil, even tropical bluetongues do it. There is some dispute in the literature as to whether there is a placental connection between mother and unborn babies, as there is in some other smaller skinks, though the weight of opinion is that there is. The young are large, and Shinglebacks T. rugosa generally have only two at a time; other species may have more.

Shinglebacks are also unusual among lizards in forming lifelong pair bonds; at the start of each breeding season they will seek each other out and remain together for the next couple of months until they mate and then go their own way again until next year.

Shingleback pair, Nullarbor Plain, South Australia.
This is the most physically aberrant of the group, and perhaps the most unusual skink in the world.
Widespread across inland southern Australia, it has attracted names including Bobtail, Stumpy Tail,
Pineeone Lizard, Boggi (or Bog-eye) and Sleepy Lizard, the name I grew up calling them.

I have a great affection for Sleepy Lizards, having followed them around the paddocks at the back of our home north of Adelaide when I was little, and later kept them in a big lizardarium in the back yard in Adelaide (in the days before protective legislation restricted the keeping of native animals).

They are mostly animals of the hot inland - and I couldn't imagine how many I've moved off outback roads to safety in my time - but they reach their south-eastern limits in the high cool country near here, just coming into the northern part of the Australian Capital Territory. Interestingly, at these cold limits, the local Shinglebacks are completely black, to maximise sun absorption.

Shingleback, Mulligans Flat Nature Reserve, Canberra.

Bluetongues always makes me smile fondly when I see one - and I'm sure many people reading this will have stories and good memories of these slow, gentle Australians. Here are some portraits to finish with.

Blotched Bluetongue, Namadgi National Park.

Eastern Bluetongue, Kakadu National Park.

Shingleback, Nullarbor National Park, South Australia.

Western Bluetongue T. occipitalis, Nambung National Park, Western Australia.
Despite the name this species is found from the Indian Ocean to south-western New South Wales
and western Victoria, substantially overlapping with the Eastern Bluetongue in South Australia.

The only species missing from this gallery (apart from the frighteningly rare Pygmy Bluetongue) is the Centralian Bluetongue T. multifasciata, an omission I can't readily explain. One day...

Blueys, a good part of the Australian landscape. I hope you've enjoyed meeting or remeeting them.

[By a bizarre coincidence, just 24 hours after I posted this my friend Harvey Perkins posted a similar offering here on his excellent blog. It's worth visiting for his photos alone.}

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