Mainly active during the day, Darwin’s frog frequently basks in sunlight, while camouflaged amongst the leaf litter. This species mainly feeds upon insects and other small invertebrates, which it catches by remaining motionless and waiting for the unsuspecting animal to come near, before lunging forwards and devouring its prey. When threatened Darwin’s frog will play dead, rolling onto its back and lying motionless, or, more dramatically, it will leap into a stream, and float in the water on its back, again feigning death (2).
The male Darwin’s frog produces vocalisations throughout the year, but mainly during the breeding season, which occurs from November to March. After encountering a prospective mate, the male leads the female to a sheltered site where courtship and egg-laying take place. The female deposits a clutch of around 40 eggs, each four millimetres wide, in the leaf litter, which are fertilised by the male. The female then departs, but the male remains with the eggs, guarding them while they develop (2). After around 20 days, when the tadpoles begin to wriggle within the eggs, the male uses its tongue to pick up the eggs, and manoeuvres them through the slits in its mouth into the vocal sac (2) (4). Here, the tadpoles hatch from the eggs and remain while metamorphosis takes place. While in the sac, the tadpoles are sustained by the remainders of the yolk from the egg, as well as nutrient-rich secretions produced by the adult (2). Once development has progressed to the point where the young are around 1 cm long and the tail has become reduced to a small stump, they move out of the vocal sac and are released by the male out of the mouth (4). As many as 19 tadpoles may be brooded by a single male, causing the internal organ’s to distort to accommodate the mass of offspring, but returning to normal after the froglets are released (2) (4).