Burrows of desert-adapted frogs, Neobatrachus aquilonius and Notaden nichollsi

The non-cocooning frogs, Notaden nichollsi and Uperoleia micromeles, and the cocoon-formingfrog, Neobatrachus aquilonius, burrow underground to survive in the hot, dehydrating arid interiorof Australia. By four to six months after these frogs had burrowed, the only surface evidence that afrog had dug a vertical burrow was either a small raised-side crater ranging from 50 – 60 mm indiameter or a shallow depression the same size with a less compacted centre. Notaden nichollsi andU. micromeles were dug from poorly-defined, sand-filled burrows in sandy soil (1.4 – 4.1% clay andsilt, 95.9 – 98.4% sand) at 600 to 2400 mm below the surface. Multiple N. nichollsi and U. micromeleswere located in single burrows. In contrast, N. aquilonius were found in clay soil (12.5 – 17.9% clayand silt, 82.1 – 87.5% sand) in burrows 280 to 1200 mm deep. At a clay pan site only a single N.aquilonius was found in each well-defined, loosely filled burrow that we excavated. From a swalesite, on one occasion we found two N. aquilonius in one burrow, and on another occasion we founda N. aquilonius and a N. nichollsi in the same burrow.