Overview
The Barking Gecko (Underwoodisaurus milii), also known as the Thick-tailed Gecko, is one of southern Australia’s most distinctive and vocal nocturnal reptiles. Instantly recognized by its deep purple-brown velvet skin studded with luminous white pearl tubercles and its fat, carrot-shaped tail, this charismatic predator is celebrated for its startling acoustic defense display when confronted by predators.
Biology and Physical Characteristics
Underwoodisaurus milii possesses a large, broad triangular head with prominent golden-yellow eyes featuring vertical pupils. Its dorsal velvet-like skin varies from reddish-brown to rich purple-black, exquisitely dotted with transverse bands of raised, bead-like white or pale yellow tubercles. Its swollen, flattened leaf-like tail functions as a critical fat storage organ, sustaining the gecko during cold winter periods and prolonged resource scarcity.
Behavior and Ecology
Strictly nocturnal, barking geckos spend daylit hours sheltering underneath large granite exfoliations, rotting hollow logs, or abandoned burrows. At night, they emerge to stalk invertebrates across open leaf litter with steady, cat-like precision. When cornered by a threat, the gecko raises itself stiff-legged off the ground, arches its spine, whips its swollen tail, and lunges forward while emitting a surprisingly loud, explosive coughing bark or rasping growl.
Conservation and Human Impact
Currently evaluated as Least Concern, the barking gecko is widespread and resilient across southern Australia, frequently inhabiting rural stone walls and woodpiles. However, widespread destruction of surface rock (rock-turning and granite collection for landscaping) and clearing of fallen deadwood in woodlands destroy essential diurnal shelter sites. Habitat conservation frameworks advocate leaving fallen timber and surface stones undisturbed.
Interesting Factoid
When threatened, this bold little gecko stands up on its tiptoes, arches its back like an angry cat, and barks with a loud, raspy growl designed to startle predators into backing off.
Last updated: October 2026