Tracks in the sand

on 18 Sep 2014 

Since our quarterly newsletter was renamed Bush Tracks, staff on the ground have been briefed to keep an eye out for prints of use for the masthead. Ecologist Vanessa Westcott sent these in from our Eurardy Reserve in mid-west of WA.

It was identified as a thorny devil. The tracks show four legs sinking deeply into the sand. They're not suggestive of a hopping motion or 'swimming' like goannas or bearded dragons and there's no sign of a tail drag.

Thorny devils have a very unusual gait that could be best described as a slow, stutter walk, often stopping to rock back and forth (you'll see what we mean in the video below). This might be a defence mechanism to confuse predators when they're spotted in the open.

They're pretty unique little lizards that have developed various methods of protecting themselves and surviving in harsh Australian outback environments. They can grow up to 20cm long and live up to 20 years.

Thorny devils live predominantly in arid and desert areas, feeding on ants. As predators they're not quick but thorny devils are nothing if not patient, finding ant nests and simply waiting until a line of ants walks by. They can consume up to 5,000 ants in one meal!

The spines all over their bodies are their most obvious defence - they don't present as easy to swallow. They also have a false head on their back or neck, so if threatened they'll lower their real head for protection and present this instead, while inflating their chests with air to appear bigger. 

The spines also help with camouflage - the bodies of these amazing critters are able to change colour depending on their surroundings.

Perhaps their most amazing feature is their ability to collect water. Dew that collects on their bodies at night can be channelled to their mouths via special grooves between the spines. And when the rains come capillary action allows devils to effectively suck in moisture from all over their bodies - an amazing adaptation to a harsh, dry habitat.