Juvenile Frogs May Camouflage Selves as Animal Poo

The young offspring of a frog native to Southeast Asia display an "unusual color pattern", probably to camouflage themselves "as animal droppings" to escape predators, according to a study. 

 

A team of researchers studying juvenile Wallace's flying frogs (Scientific name: Rhacophorus nigropalmatus) – which are bright red with small white dots – made the findings thanks to an experiment at Schoenbrunn Zoo in Vienna, Austria, the zoo reported on October 12, 2023. 

 

"The young frogs probably count on the fact that they will be seen but considered something inedible", University of Vienna researcher Susanne Stueckler (right) said. She and others had published their findings in the journal Behavioral Ecology and Sociobiology. 

 

To test their hypothesis that the frogs were trying to escape predators, the researchers created differently colored wax frog models and placed them in the zoo's rainforest house. The house "contains a diverse community of avian predators that are well known to use color vision to detect frogs as prey", the study noted. 

 

It found that the attack rate was significantly greater for red than for green but was reduced by half when red models had white spots. 

 

"We show that the unusual colour pattern of juveniles likely functions as a masquerade of animal droppings", the researchers said. "(It may) function as anti-predator strategy... so that predators misidentified them as inedible objects".

 

According to them, to their knowledge, this is the first experimental exploration of a vertebrate masquerading as animal droppings. 

 

The frogs' spots disappear after one year, when individuals mature into adults and develop their iconic emerald green color. 

 

Wallace's flying frogs live mainly at mid-canopy level of tropical rainforests – and their extensive webbing allows for long glides from tree to tree. The species can be found at ground level when it descends to mate and build its bubble nest.