Should you ever find yourself standing on a high, wet heath in south-east Australia and shout loudly, either due to being lost or from general confusion, you may hear a “squelch” in reply. It sounds like someone wringing a rubber chicken’s neck, but don’t worry, it’s not the bunyip – just a male northern corroboree frog telling you to a) get off his turf or b) come and check out his turf, sexy lady!
If you choose b), ignoring the disappointment you’re sure to inspire, you’ll see a teeny frog with black and near-neon yellow-green stripes that could fit snugly in the palm of your hand. You’ll also see a nest of eggs from various lady friends, which he’ll guard until the end of the summer before retreating into nearby woodland.
Both parents and eggs know how to weather the elements, with Dad and long-gone Mum going into inactive “torpor” in winter, and the eggs freezing development via “diapause” until rain or snow melt triggers them to hatch. When this happens, you’re about as likely to still be stood there as to see this in the first place, because there are currently only 20 northern corroboree frogs left in Australian Capital Territory and about 1,000 in New South Wales. And not because it’s too mouthy.
In fact the northern corroboree frog wants the attention so predators know it’s poisonous. Named after an Aboriginal word for meeting, where people are similarly adorned, the corroboree frog’s vibrant stripes are like a human fingerprint, but that’s far from the only unique thing about it.
Along with its even rarer southern relative, it’s the only vertebrate that can make its own alkaloid poisons (pseudophrynamines) as well as from its food (pumiliotoxins) like other poisonous frogs. It could be lethal if ingested by mammals, but it’s not the reason you’d need a pair of gloves to handle it.
Frogs breathe and balance salts through their skin, so anything affecting it can cause trouble. Cue the global amphibian epidemic of chytrid fungus, and just one of the reasons the northern corroboree frog isn’t long for this world.
By attacking the parts of its skin that contain keratin, the fungus essentially suffocates and then stops its heart, and has had a devastating effect on many a frog species, with 6 of them believed to have been wiped out in Australia alone. That’s before we get to climate change messing up its breeding sites and egg success, or the feral hoofed animals trampling all over said nesting sites. On top of this, the northern corroboree frog has a breeding age of 4, which is geriatric by some amphibian standards. Fortunately, this zingy-looking frog has a helping hand.
Chytrid fungus can’t affect eggs or tadpoles due to the lack of keratin, and some captive breeding programmes, such as in Tidbinbilla Nature Reserve, can boost the egg survival rate from 10% to up to 90%. Not bad for a centre in a pair of shipping containers! Also, being cold-blooded means heat affects its maturity, so in 2019-2020, there are plans to release captive-bred frogs at lower, warmer elevations, so they’ll be ready to get jiggy at 2 years old instead. But what’s the point if the adults can still be infected?
Through breeding, some other frog species have developed an immunity to chytrid fungus, so this is another possible leap for the northern corroboree frog. Unfortunately, rather than hop, it chooses to walk everywhere on web-less feet, but with enough conservation support it may be able to bounce back.
Latin: Pseudophryne pengilleyi
What? Teeny, brightly coloured poisonous frog
Where? Australia, in Australian Capital Territory and New South Wales, mostly in wetlands and sub-alpine woodlands
How big? 2.5-3 cm / 0.98-1.5 ” long, could fit very snugly in the palm of your hand
Endangered? Yes, as per IUCN Red List of Threatened Species, due to infection from chytrid fungus, habitat destruction, and weather changes affecting its breeding grounds.
Probable motto: I don’t hop, I want to show off my stripes.
They look interesting. Do they need my help at all?
Yes! Fortunately there are several agencies scrambling to save this chipper little frog before it’s crushed under the boot of chytrid fungus, climate change, hoofed animals, and to top it all off, its own low reproduction rate.
Both the northern and southern species have their own campaigns via the Corroboree Frog Recovery Program.
Sydney’s Taronga Zoo released 270 eggs and tadpoles earlier this year and could use some additional support.
If you live locally, the New South Wales Office of Environment and Heritage has various projects on the go as well as tips to help froggies in your area.
Just to prove I’m not fibbing
Australian Geographic. 2014. “Saving the Australian corroboree frog“. YouTube.
Colley, Clare. 2014. “Endangered northern corroboree frogs released into Brindabella National Park“. The Canberra Times.
“Corroboree Frogs have a typical amphibian life-cycle with an aquatic tadpole stage and terrestrial frog stage“. No date. Corroboreefrog.org.au
Daly, John W. 2002. “Australian frog is first to make its own chemical weapons“. EurekAlert!
Gough, Miles. 2016. “Australia frogs ‘could be wiped out by killer fungus‘”. BBC News.
McFadden, Michael. 2018. “Eggs release brings hope for northern corroboree frogs“. Taronga Zoo.
McNeilage, Amy. 2018. “Faster reproduction could hold key to saving critically endangered frog“. The Guardian.
“Northern Corroboree Frog“. No date. Zoos Victoria.
“Northern Corroboree Frog“. 2015. ACT Government.
“Northern Corroboree Frog – Profile“. 2010. New South Wales Office of Environment and Heritage.
“Northern corroboree frog (Pseudophryne pengilleyi)”. No date. Arkive.org.
“Pseudophryne pengilleyi “. No date. IUCN Red List of Threatened Species.
“Pseudophryne pengilleyi“. No date. Canberra Nature Map.
Taronga Zoo Sydney. 2018. “Keeping an eye on northern corroboree frogs in the wild“. YouTube.
“Zoos Victoria’s Priority Species: Northern Corroboree Frog“. No date. Zoos Victoria.
Featured image credit: “Northern Corroboree Frog” by R_P_F