Asian Treefrogs May Practice "Parenting" to Combat Environmental Pressures

An unusual parenting behavior has been identified in a particular species of Asian treefrogs that no other treefrog species appears to exhibit. Researchers suggest that this may be a behavior that developed in order to combat harsh environmental pressures.

Asian treefrogs are not known for being good parents. In fact, few frogs are, as parenting strategies are only commonly seen among mammals, birds, and some marine life.

According to researchers from the Department of Biological Sciences at the National University of Singapore (NUS), the Asian treefrog Chiromantis hansenae is found primarily in the northeastern forests of Thailand and parts of Cambodia. This tiny amphibian lays a significant number of eggs at a time in order to increase the chances that at least a couple of the offspring will survive until adulthood. However, unlike most treefrogs, the C. hansenae also performs what experts call "egg attendance" to further increase the chances of offspring survival.

Egg attendance is the most common form of parental care among amphibians and involves a parent (usually the father) sitting on his eggs to keep them moisturized and protected from the elements. Egg attendants often briefly leave their eggs to soak up more water, but otherwise spend their time covering their delicate young until they hatch and can find shelter for themselves.

According to a NUS press release, what is unusual about C. hansenae taking up this practice is that it births young that do not hatch as frogs, but begin in a free-swimming tadpole stage. Additionally, the mother, not the father, stays with the young for the entirety of this process.

According to researcher Ms. Sinlan Poo, this unique and unusual take on amphibian parenting goes to show how much is still unknown about the tiny animals.

"Our study is the first experimental investigation of parental care in Southeast Asia, a region with over 700 species of amphibians," she said. "This highlights the need for more of such natural history studies."

According to the researchers, while the exact evolutionary cause for why these tree frogs in particular developed this behavior remains unclear. A study of the changing nature of the frogs' habitat revealed that their parenting practice is actually saving their young from drying up and dying, despite being so close to water.

A NUS press release detailing these findings was published on May 28.

The discovery was also published for the May issue of Natural History.