 Sources say frogs use low frequency sound of rain as a cue to emerge from aestivation.While olfactory cues are considered a secondary emergence stimulus, there is evidence in other anurans that the smell of emergent plant growth can also guide frogs to breeding sites, specifically pond weed species.Persistent emergent behaviour has been observed personally when a piece of moss was placed in an enclosure of two captive "Spea bombifrons".