back to article Biologists track down elusive lungless frog

Scientists from the National University of Singapore have described a rare lungless frog which appears to absorb oxygen through its skin. Barbourula kalimantanensis. Pic: National University of Singapore The university's team, led by evolutionary biologist David Bickford, spent two weeks scouring the remote Kalimantan region …


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  1. Dr. Mouse

    Me Too

    "Amphibians may be more prone to lunglessness since they readily utilize other methods for gas exchange."

    I have always used other forms of gas exchange.

  2. Marvin the Martian

    "Breathing through skin" comes standard!

    Don't be too surprised that it must be "breathing through its skin" if it doesn't have lungs --- that comes with being an amphibian (or a reptile, to some extend).

    The smaller you are, the simpler your gas-exchange (air, carbondioxide) can be --- hence little insects all breathe through diffusion.

    Even large adult bullfrogs breathe 20% of their O2 through the skin (and exhale 75% of their C02 through it). For frog larvae (who have gills) it's usually both around 60-70%. For salamanders like the Hellbender it's 90% and 97%, and for the lungless salamander Ensatina eschscholtzii it's 100% and 100%. [I'm quoting from Kardong (1995) now.]

    To increase skin-breathing you can have a large amount of floppy skin like the Hairy frogs have --- even to the extent of living at great depths (with little oxygen) and never surfacing to breathe, like the Titicaca frog Telmatobius culeus does. This frog still has lungs, but ineffectual ones.

    Even turtles, lizards and snakes get about 10% of their oxygen through the skin, and exhale around 25% of CO2 by skin (very species-dependent percentages). Also, there are very few species of snake with 2 (functioning) lungs, the left one being reduced to almost nothing.

  3. JP

    Heading a little quicker towards extinction...

    How on earth does Bickford decide that the frogs are lungless?

    Does this involve slicing the poor, endangered beastie open, to spill its guts and secrets for the scientist?

    And what reason would someone have to look for a lungless animal?!? "Hmm. That frog looks particularly flat. I wonder if it has lungs?"

    Guess I would never have discovered it...

  4. Ru

    Severely flat?

    That's a term I'd associate with frogw that have undergone a road/tire assisted metamorphosis, rather than one which was merely vertically challenged.

  5. Lisa Parratt

    Re: Ru

    I think you mean "Dimensionally transmogrified".

  6. Steve
    Thumb Down

    Backwards title

    It's not 'backwards' evolution unless you know something the frogs don't and they actually require lungs.

    As an adaptation to the environment they are in I'd guess that it works perfectly well, so it's the bog standard forward variety of evolution.

    There is really no such thing as backwards evolution or devolution. The only time that phrases come out like this are when we mean it's evolving in a direction that for some reason we've decided isn't correct, which invariably means that we are wrong about what is correct for that environment.

  7. Magnus

    Backwards Evolution?

    What are you on about? If lungs are a disadvantage in your current environment and you don't need them to survive then why should it be a "backwards" step to lose them?

    Then again it does make things slightly awkward when the water turns "warm and turbid" and you suddenly can't breathe anymore...

  8. Ferry Boat

    How does it smoke?

    Just wondering.

  9. Anonymous Coward

    That's no frog...

    ...that's Bill Ray! Of whom (grammar) we're not afraid.

    Mine's the t-shirt with 'geeky techie nerd' emblazoned on it.

  10. Stuart Gray

    Reminds me of the Kevin Bloody Wilson song

    "I've got a tongue, that's ten inches long, and I've learned to breathe through me ears"

  11. Anonymous Coward


    "but we were able to re-discover two new populations upstream"

    How can rediscover something that's new?

    Just wondering.

  12. Natalie Gritpants Silver badge

    What women want

    Is a man with an eight inch tongue that can breath through his skin.

  13. Edward Rose


    @Ferry Boat:

    Without getting lung cancer?

  14. Anonymous Coward
    Anonymous Coward

    @Lisa Paratt

    Dimensionally transmogrified ?

    You wouldn't happen to have a cat called frisby by any chance ?

  15. Greg

    Why criticize "backwards"?

    "Backward" evolution is actually a well-chosen title.

    Of course, it's not backward in the sense that it's bad for the frog, or ineffective in the environment.

    Otherwise, it would be titled "Bad Evolution" or "Ineffective Evolution".

    It is indeed a backward evolution (at least if lungs were lost), in the sense that lungs appeared at some point in time, and then a characteristic of those frogs was brought backwards to the time when animals (or frogs' ancesters) did not have lungs.

    I fail to see anything wrong here except for the desire of people to grumble on something to show off how much they know.

    Last time I checked, "to go backward" didn't mean "to be mean, bad, most probably completely stupid and unadapted". It just meant "to go back to a previous location". These frogs went back to having no lungs and thus, their evolution went backwards.

  16. Alan Paul

    Backwards Evolution

    Are we not frogs? We are DEVO.

  17. Sean Aaron

    re: Greg

    Unless you know the evolutionary history of this particular species, the idea this is backward evolution makes no sense. My impression was this was a species that NEVER had lungs, therefore it cannot be regarded as devolution unless you have confused ideas that evolution==progress and therefore lungs > no-lungs, neither of which is correct.

  18. Ash

    @Ferry Boat

    Tickly at the back of the throat, quite oily. Best dried before rolling.

    Anyway, all we need is the same stuff that lines our stomachs to line our blood vessels and we wouldn't need to breathe at all.

  19. Greg

    @Sean Aaron

    If indeed it never had lungs, then I agree with you of course.

    But then the question is not on whether the evolution is backward or not, it's not even an evolution at all.

    We just saw something that never evolved to get anything related to lungs and stayed at the primal, historical way of dealing with the need for O2.

    The troublesome word is Evolution, not "backward"

  20. J

    Re: re: Greg

    "My impression was this was a species that NEVER had lungs"

    That would be wrong, I'm afraid.

    Unless you define that it would only be "that species" after it lost the lungs, but a different species before. Which would be pointless anyway. But I have the impression that's not what you meant... was it rather that its lineage never had lungs? Wrong.

    That frog kinda looks like the alien, specially the eyes...

  21. Mike Richards Silver badge

    James Bond

    Now what would happen if you cover its skin with gold?

  22. bogsheet

    Surface area...

    Being flat does not increase the surface area of the frog!

    It increases the surface-area-to-volume ratio! Doh!

  23. Ishkandar

    @Mike Richards

    No chance !! Some local bastards nicked all the gold and left a mess behind them, as per usual !! Say so in the article !!

  24. Aubry Thonon

    @Ferry Boat

    "How does it smoke? "

    I don't know - I never set fire to one...

    ...leaving now...

  25. Franklin

    "Backward evolution"

    In this context, "backward evolution" means loss of an organ which a previous ancestor had. If this species of frog shares a common ancestor with other frog species, and that common ancestor had lungs, there you go.

    Not really great usage of the term, to be sure, as words like "backward" do carry connotations of evolution working in a predefined direction (which it does not), but at least it's possible to see where the author is coming from. Though I think you could say our own loss of the appendix and our tails is also "backward evolution."

  26. Steve
    Thumb Up

    It's still not backwards @Greg

    Just because you had something in the past and then evolve to no longer require it (which may have also been the case in the past) does not mean that the evolution is backwards.

    Evolution is by definition an ongoing process to cope with the current environmental situation, loosing unnecessary lungs is no more backwards than our loosing tails.

    'Frog evolves to more closely resemble distant ancestor' might be more accurate, although longer.

    Or just 'Evolution in Borne' to keep in the style used by the author.

  27. bogsheet

    Our own loss of the appendix?! @Franklin

    I think perhaps you should revise your human anatomy.

    Ever heard of appendicitis? Not that rare a human condition, it would be difficult to have this if humans had evolved to no longer have this organ.

    Perhaps you are confusing some biology lesson from years ago where it was argued that the appendix no longer performs a critical function in humans and can be safely removed if infected without significant impact on the person.... unless they live on grass.

  28. Anonymous Coward

    backward evolution

    I think that this was an enjoyable article. I also agree with that maybe 'backward' was not the best word - however it did get the point across. If this particular family of frogs ancestors did infact have lungs then it seems perfectly reasonable that the evolution (which it certainly is) could be described as a devolution. This in the sense as mentioned by others because if something has appeared in the particular line of animal before and then 'dissapears' it is by definition 'devolved'. However in a case when the difference between ancestor and the current family is significant one could ofcourse also choose to call it a revolutionary evolution.... or the shorter version a revolution...

  29. Danny

    Not evolution but adaptation

    Being that there is a severe lack of of ID or creationist's viewpoint here- I would have to point out that this is not evolution at all. Unless you can prove that genetic information was gained there is now way you can call this molecules-to-man evolution whether it is backwards or forward. It is more likely that genetic information has been lost in this species. Unless you have not noticed a loss of genetic information works against the idea of evolution. See finches, cave spiders, and fruit flies for examples of a loss of genetic information leading to adaptation. You guys have it backwards. Genetic information is being lost, not created. God created all life but it is slowly eroding genetically since the fall. See Genesis. Let the blasting away begin! And sorry for any spelling or grammatical errors. After all I am American and a creationist so I am basically at caveman level by evolutionary standards.

  30. bogsheet


    Well I think it is particularly notable if not amusing that the argument from the "creationist" who just joined the debate says that unless we can *prove* something, we can't make a conclusion based on that assumption!

    I barely even feel it necessary to finish my retort, as I'm sure you can see it coming. Incredible really that the argument picks a couple of examples from nature to try and lend itself credibility. What of all the other numerous examples that support the hypothesis of evolution?

    But anyway there is little point trying to defend evolution from scientific stand point when faced with an attack from someone who proposes completely foundless non-scientific fairy-tales as their counter. See Genesis? I'm glad I still have my sense of humour in tact, as the last time I checked Genesis was a book written by men a couple of thousands of years ago who then passed it down to us via a process akin to Chinese whispers. I'm not sure if I would want to believe anything people believed thousands of years ago, as they were without the benefit of scientific thinking and knowledge... At least they had an excuse for believing that God created the Earth - they had nothing better to choose from. For people nowadays there is no such excuse.

  31. Anonymous Coward
    Anonymous Coward


    Well leaving aside the inevitable arguments, I'd just like to know the rationale behing the statement "Unless you have not noticed a loss of genetic information works against the idea of evolution".

    I mean, the length of DNA and number of chromosomes varies from species to species, and I'm not sure there's a _required_ correlation between this and 'forward' (in the sense of time) evolution. Surely that's only true if you assume that the 'purpose' of evolution is to accumulate data. But does evolution have a purpose? I think not.

  32. Danny

    evolution proven?

    so bogsheet, by your arguments, evolution is a proven fact, (and what was the name of the scientific study that proved it?) I believe in "completely foundless non-scientific fairy-tales" because I don't use random chance to explain how the universe miraculously appeared from nothing, (I guess Einstein and Newton were idiots huh, and definitely not scientists) Genesis was written 2000 years ago, (maybe 4000 is closer but who's counting right?), and ancient people were imbeciles because they did not have the glorious gift of science. (So science is a recent invention? You are such a genius! Why didn't I see it before! Um wait, science has been around since the first person asked "why", never mind. Oh, and you also said...

    "For people nowadays there is no such excuse."

    But check this out...

    "For since the creation of the world God's invisible qualities—his eternal power and divine nature—have been clearly seen, being understood from WHAT HAS BEEN MADE, so that men are without excuse." Romans 1:20 (emphasis mine)

    You can call me unscientific all you want but some of the greatest scientific minds of all time believed in God the creator. In fact, they felt that science explained how God operated in the natural world. It is only recently that the high priests of evolution have tried to squash all opposing views and declare that anything other than a completely natural explanation means that you are in no way scientific.

    I don't subscribe to your religion.

  33. Anonymous Coward
    Paris Hilton


    Errm - evolution is not random chance. As in 'not'. That is quite well understood by anyone who gives a microsecond's thought to the matter.

    As for being a 'religion', I'll let you know when I kneel down and pray for forgiveness to evolution.

    Other than that, funny; very funny.

    Paris - cos the amount of plastic and rubber must mean she's evolving into a higher life form

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