All frogs have lungs, right, because otherwise they couldn’t breathe. Well that’s what we used to think – until now. Scientists have discovered a frog that doesn’t need lungs – instead it breathes through its skin, like fish do.
But wait a minute… since frogs are amphibians and spend a lot of their lives in water, why would they have lungs anyway? In fact, all frogs can breathe through their skin, but most frogs also have lungs so that they can cope with being out of water for long periods of time. That’s what makes this new frog species so unique – it has got rid of its lungs and gone to gills-only, as if it was evolving back into a fish again.
Why would it want to do that? This particular frog lives in fast-flowing, cold waters (on the Indonesian island of Borneo). Fast cool water contains more oxygen than still warm water, so it can get more oxygen directly from the water than most frogs can.
Also, it has a lower metabolic rate than other frogs, meaning it doesn’t need as much oxygen anyway.
However, scientists are still puzzled as to why the frog would want to get rid of its lungs entirely. After all, frogs’ noisy mating sounds require lungs, so surely any species that lost its lungs would not be a successful breeder – at least that’s what we used to think until this species was discovered.
Maybe the new species survived fine staying in water all the time, and having lungs was a waste of energy – we really don’t know. One theory is that the loss of lungs enabled the frog to become flatter, and get a bigger surface area. Bigger surface area means more space for air to enter through the skin.
Scientists hope to carry out much more research into this new species, although environmental factors like mining and climate change could make it extinct before we have a chance to discover all its secrets. And what a tragedy it would be to lose this intriguing creature before we even got to know it properly.