Earth's only lungless frog caught between rock and hard place

William Atkins
Monday, 07 April 2008 23:58

Science - Biology

Scientists currently are leaning toward that theory that the frog once had lungs long time ago but had difficulties going from the surface to the bottom of fast-moving water in cold streams because of the buoyancy of air-filled lungs.

Thus, the frogs slowly evolved from breathing through lungs to breathing through their skin, and eliminated the presence of lungs in their bodies.

Scientists already know that amphibians rarely breathe through their skin because it is more difficult to get sufficient oxygen into their bodies than with the process of breathing through lungs.

Only cold-blooded animals breathe through their skins because they don’t move as much, so do not expend as much oxygen.

The scientific community knows of only one family of salamanders and one species of caecilians that are lungless amphibians, besides B. kalimantanensis.

For the lungless frog whose habitat includes cold water, the low temperatures of its water holds more oxygen than warm waters, which is desirable. Plus, rapidly flowing streams allow more oxygen to flow over the body of the lungless frogs than slowly moving streams, which is also beneficial for the frogs.

So, with its habitat being clear, cold, fast-flowing streams, the lungless frogs are very happy living in such streams in Borneo.

However, these streams are increasingly being altered by the actions of illegal gold mining operations and land conversion techniques such as deforestation.

Both operations are being done by native peoples who are poor and are only trying to make a living, a meager living at best.

Thus, the lungless frog is caught between a rock (gold nuggets in mining operations) and a hard place (increasingly hostile environment that is turning cold and fast-moving waters into warmer and slow-moving waters).

The team of scientists researching the lungless frog does not know how many frogs remain in existence in Borneo.

They are not telling anyone where these frogs are located so that poachers and other people cannot disturb their environment any more than already being harmed.

Currently, two known populations of the frog are known to exist.

Bickford remarks about the dilemma, “This is an endangered frog—that we know practically nothing about—with an amazing ability to breathe entirely through its skin, whose future is being destroyed by illegal gold mining by people who are marginalized and have no other means of supporting themselves. There are no simple answers to this problem.” [EurekAlert]

The result of the research is published in the April 8, 2008 issue of the journal Current Biology, part of Cell Press.

The research team included David Bickford, along with Djoko Iskandar and Anggraini Barlian, of Institut Teknologi Bandung, Java, Indonesia.