The Emei music frog accurately tells potential mates about the structure and quality of the nest he has built through his calls.
Although females of some frog and bird species size up mates through male song, only human males were thought to vocally advertise their real-estate assets. However, research from Yezhong Tang at the Chengdu Institute of Biology in Sichuan, China, and his colleagues shows that calls made by male Emei music frogs (Babina dauchina) from inside nests differ in frequency and note duration from those made outside.
What is more, call characteristics were positively correlated with the area of the burrow entrance and burrow depth. More than 70% of females studied preferred calls made from inside nests.