Skip to content

Species of the Week: Bornean Flat-Headed Frog

By on October 31, 2011 in Species of the Week, Uncategorized

This flat looking frog has one extremely unique quality: it is the only known frog in the world to have no lungs! The Bornean flat-headed frog (Barbourula kalimantanensis) is ranked 152 on the EDGE Amphibians list, and is classified as Endangered by IUCN.

Lungs are pretty crucial for the survival of most tetrapods (amphibians, reptiles, birds and mammals) since they allow land dwellers to get oxygen from the surrounding air. It is rare therefore, for species to evolve a lungless existence. Yet this has happened in three independent occasions all within the wonderful world of amphibians. There are over 375 species of lungless salamanders, one species of caecilian, and of course this one frog.

It looks like losing its lungs was the best bet for this extraordinary species. These frogs live in clear, rocky, fast-flowing cold rivers in moist tropical forest. Having no lungs in this environment makes it easier for the frog to sink down to the bottom of the stream and hide under rocks. Lungs full of air on the other hand, could mean floating away on the current.

Like other frogs, the Bornean flat-headed frog is able to absorb oxygen through its skin. But while most species only absorb little oxygen this way, the characteristics of its body and habitat allow this species to get all the oxygen it needs this way. It has a flatten body and broad a head which give it more surface area though which to absorb oxygen. Combine this with fast flowing cold water that is richer in oxygen, and no lungs is no longer a problem!

We still know very little about the biology and ecology of the endangered Bornean flat-headed frog. Sadly its habitat is fast disappearing to illegal gold mining and deforestation. But this extraordinary species is surely worth saving, so spread the word and help secure a future for weird and wonderful EDGE species!