Tusked Frog

Fascinating facts about the Tusked Frog

• Both sexes have a pair of bony tusks that fit into special grooves on the upper jaw when the mouth is closed; the male’s tusks are larger, giving the frog its name.
• Male tusked frogs are the only Australian frogs where the male outgrows the female – up to 5 cm versus 4 cm – and they also sport a disproportionately large head. The oversized head and bigger tusks help males lock jaws in combat, a behavior compared to deer antlers clashing for dominance. Those fights have driven the species’ striking sexual dimorphism.
• During the breeding months of October to December, a male builds a floating foam nest hidden from sunlight in ponds or dam edges. He then deposits up to 600 white, pigment-free eggs into the foam and guards the mass until the tadpoles hatch. This secretive, bubble-wrapped nursery protects the clutch in the wetland’s harsh glare.
• Tadpoles stay in the water for two to three months, growing to 3–3.5 cm before they metamorphose into tiny “mini-adult” froglets.
• The IUCN lists the tusked frog as Near-Threatened, with a dramatic decline linked to the fungal disease chytridiomycosis and habitat loss from urban and farm development. In New South Wales’ Southern Tablelands, the population is officially endangered after disappearing from much of its historic range. These pressures show how a once-common rainforest dweller can quickly become a conservation priority.

At a glance

About the Tusked Frog

The tusked frog (Adelotus brevis) is a compact ground-dweller that roams the rain-soaked margins of dams, creeks and flooded grasslands from Eungella National Park in Queensland down to Ourimbah in New South Wales. Males reach about 5 cm, females 4 cm, and both sexes bear a pair of tiny, curved bony protrusions on the lower jaw that resemble miniature tusks, visible only when the mouth opens. These “tusks” slot into matching grooves on the upper jaw, a feature unique among Australian frogs, and they grow larger in males, whose heads are disproportionately massive compared to their bodies. The dorsal skin ranges from brown to olive-black, dotted with low ridges, warts and a characteristic butterfly-shaped marking between the eyes, while the ventral side dazzles with a marbled black-white pattern punctuated by flashes of red on the groin and hind legs. Their cylindrical, unwebbed digits are adapted for navigating leaf litter and shallow water. During the spring-summer breeding season, males construct hidden foam nests in the leaf litter of streams and dam edges, calling a terse “tok-tok” that echoes faintly through the understory. Each floating foam mass can cradle over 600 white, pigment-free eggs, which the male guards until they hatch. Tadpoles develop over two to three months, reaching 3–3.5 cm before metamorphosing into miniature froglets. A striking, almost ritualistic behavior sees males lock jaws, much like deer antlers, fighting for dominance, a contest that likely drove the evolution of their oversized heads and pronounced tusks.

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