EPOW - Ecology Picture of the Week

The Curling Tail Skink

Two-spined Rainbow Skink (Carlia amax), Family Scincidae
Northern Territory, Australia

Explanation:  This diminutive lizard has a tail that wriggles and curls.  But why?

Check out this brief video I shot in Litchfield National Park, "Top End" of Northern Territory, Australia ... showing this skink wiggling and curling its tail:

This is a two-spined rainbow skink, one of many skink species found in Australia.  But this one is unique in its tail-coiling behavior.  

The behavior probably evolved as a distraction display, mimicking a vulnerable worm or snake, so as to misdirect potential predators ... and there are many there! ... falcons, hawks, possums, snake, even other lizards.  A predator will be distracted and go after the tail instead of the body or head of the lizard, allowing the skink to escape to safety.  

What's even more interesting is that this tail-curling, predator-fooling behavior has evolved in other species, such as the totally unrelated complex of curly-tailed lizards (Leiocephalus spp., family Leiocephalidae) of the Caribbean.  And distraction displays, of course, exist in many other forms, such as killdeer feigning a broken wing and flopping on the ground, to lure predators away from the nest.  

Back to our week's hero.  Like many other skink species of Australia, the two-spined rainbow skink skulks among rocks and leaves and down vegetation on the forest floor, searching for its insect and invertebrate prey.  

Then I discovered the following unusual individual in Queensland, northeast Australia.  
It has a white neck band, which I've never seen in any other skink, or any lizard for that matter:

This "white-necked lizard" form was not in any field guide or publication I have seen.  I asked a local herpetologist, and the answer was a speculation that the white band could be just an artifact of an unusual exuviation (shedding of the scaly skin).  I supposed that is plausible, but it would be of great interest to return to the site to see if others of this form are also there, and if it is an authentic biological entity yet to be described.