Sandhill Frog (Arenophryne rotunda)
What does it look like?
This thick-set, ball-shaped frog has a rounded head and very short legs and toes, with loose skin around the hind legs. Its skin is so baggy that it looks like it’s wearing a suit a few sizes too big! The frog’s colour varies from off-white to cream with green, brown or brick-red speckles, but can darken rapidly to a grey or brown. It grows to just 26–33 mm long, with females larger than males.
Where does it live?
The sandhill frog spends most of its life buried in the sand on the dunes of Edel Land
and Dirk Hartog Island
. An exciting recent (2005) discovery of the frog near Nanga Bay, has extended the species’ known range. It can also be found inland, through the Zuytdorp Nature Reserve and south to Kalbarri. It avoids the heat of the day by burrowing headfirst into the sand to a depth of 10–30 cm. Sometimes its hind legs stick straight up into the air, making it look like it’s diving into the ground! Only one other Australian burrowing frog, the turtle frog, digs with its hands.
Once submerged in the damp sand, the sandhill frog replenishes its moisture reserves by absorbing fresh water through its skin. It emerges from its burrow to feed on ants and other insects after rain, or when there is a night dew. But unlike most other frogs, it doesn’t hop but crawls, one leg after the other. This little frog will crawl up to 30 m in search of a meal.
How does it breed?
The sandhill frog attracts its mate with a squelching call. Unusually for frogs, it does not need free standing water in which to breed. Instead, it lays clutches of large (up to 5 mm in diameter), creamy white eggs about 80 cm below the surface at the bottom of a burrow. And unlike most frogs, there is no free-living tadpole stage. The tadpoles develop within the egg, and the tiny young frogs emerge from their burrow after about two months.
Any threats to its survival?
In February 1978 the sandhill frog became the first amphibian to be listed under Western Australia’s Wildlife Conservation Act as fauna which is ‘rare or in need of special protection’. However, its conservation status is being reviewed as more is learnt about the frog’s biology and distribution. It appears to be common over its range although the range itself, a thin strip of coastline, is quite limited. Global warming and other climate changes may harm this special frog. Keep an eye out for its distinctive tracks, marked at beginning and end with a telltale mound of sand, and watch where you walk!
For more information about Western Australian wildlife check out the WA Museum Fauna Base
to download a printable PDF of this fact sheet.