Narrow-mouthed Frogs are specialized on small food items such as small insects. Species of Calluella (formerly Calluella), Kaloula, Gastrophrynoides, and Microhyla are terrestrial or fossorial; whereas others (Chaperina, Kaloula, Metaphrynella) have the ability to climb vegetation.
Using standing bodies of water for reproduction likely is the ancestral condition for microhylids. Some species, however, have adapted to use small quantities of water accumulating in bamboo internodia, tree holes, nepenthes pitchers etc.
The reproductive biology of Narrow-mouthed Frogs commonly includes aquatic eggs and a free-swimming larval stage with highly efficient suspension feeding.
Microhylid tadpoles generally lack expanded oral discs and keratinized mouthparts. The gill spiraculum is situated in postero-median position on the belly.
Some microhylid groups (for example, in New Guinea) have evolved terrestrial clutches and direct development, but this has not been shown conclusively for any of the Borneo species.