Taipei Zoo

In wintertime, the background sound is so distinct in the Taipei Zoo. If you pass by the entrance of the Formosan Animal Area and a large flamingo pool, you may hear male frogs making low and vibrant mating calls day and night.
 
Taipei green treefrogs are active from October to March. They are one of the few frogs in Taiwan that mate in winter. The frogs have evolved a mating system over a long period that they mate in different seasons, which reduces competition between offspring for resources and maximizes the chances of survival for healthy offspring.
 
Males and females vary in body size, with males (measured about 3.5 to 4.5 cm in length) slightly smaller than females (measured about 4.5 to 5.5 cm in length). Most females base their mate choices on strong, healthy, and larger males, so males with lower-pitched calls and larger body sizes may win the chance to mate with a particular female.