This ground-dwelling species reaches lengths up to 6.5 cm and has a powerful robust build with short limbs. The back is dark brown or grey, mottled in dirty white or light grey. The flanks behind the front limbs often show a distinctive yellow colour. Males have larger arms but otherwise show no distinguishing sexual features. In particular, male moaning frogs lack the nuptial spines found in males of the other Heleioprus species.
Prior to start of winter male moaning frogs excavate burrows in low lying areas which are likely to become inundated by winter rains. Females enter the burrows and deposit their egg mass in a chamber at the bottom of the burrow in damp soil. Rising water table or stream levels eventually flood the burrows allowing the partially developed tadpoles to wiggle free of the egg mass and swim out of the burrow. Males usually only call for a month or so after the first heavy rains in autumn.
A long, drawn out, mournful moan. Males usually call from within the breeding burrow.
The egg masses are white and foamy. As many as 300 eggs may be laid in each mass.
Moaning Frog tadpoles grow to 5 cm. The tail is only 1.5X the body length. The body is dark brown with a series of thin, light coloured lines on either side of the head and body. Tadpoles may be found in flooded burrows during early stages of development. Eventually they are washed into larger water bodies where they are usually located on the bottom close to aquatic vegetation which they use for cover when disturbed. Development time is 2-3 months.
Moaning Frogs probably bury themselves in moist sand and aestivate (become dormant) over the hottest summer months. Moaning Frogs are common in and around Perth and are frequently heard calling in gardens adjacent to wetlands, sometimes to the dismay of the residents.