In a rainforest in Queensland, Australia, in about 1980 a small frog sat on a stone in a wet place. She had conspicuously protruding eyes. At a casual glance there was little beyond that that would catch the interest of a passer-by. Except for one thing. She had been given the extraordinary name of gastric-brooding frog. How could anyone conjure-up such a name! Come on!
This frog, with no notable colouration, however, had one little trick that said she was important.
Frog’s eggs, tadpoles and babies suffer from high predation. So what is a frog to do to protect her brood? This species evolved an astonishing process to give her youngsters their best chance of survival. She laid her eggs and the male fertilized them in the normal way of frogs. Then she did an unbelievable thing – she ate them all up – like Goldilocks eating the baby bear’s porridge.
So where’s the great plan in all of that? Eating your own eggs to prevent Great Diving Beetles from doing the same seems – well – a bit dumb. It’s as though mum hadn’t quite joined up all the dotted lines to come up with a workable solution.
When food slips down into the stomach – acids break it up into nutrients – but in this frog’s case the eggs secrete a chemical that protects them from the corrosive digestive juices. The developing tadpoles and the resultant baby frogs, still in the mother’s stomach, also produce the same protective shield. And when mum frog judges the time to be right she regurgitates and spits out her brood of tiny children, one by one, to take their chances in the great world outside.
And there is another consideration here – usefulness – to us. In the USA alone up to 25 million Americans suffer from peptic ulcers; a painful condition. Could the chemical shield produced by the eggs of this frog lead to the discovery of a drug that would be a cure for this painful human condition? Scientists started to work on this possibility. Then all research stopped. Why? Because sometime in the early 1980s the gastric-brooding frog became extinct. It had taken millions of years of evolution to create this chemical – and now it had disappeared with the disappearance of this frog.
There were two different species of gastric-brooding frog. Both have become extinct. the reason is not clear. Fungal infection and damage to the bits of rainforest they needed may have been part of the cause.
That a small frog managed to evolve such a process is far beyond our understanding. We can only drop down into silence at the mystery of it all.
In her going we have lost one more wonder from our world.