Compulsive Frogging

It's a warm, moonless, Saturday night. It's raining, the cloud's down so low on the headland that it qualifies legally and scientifically as mist, and I'm wandering round in the dark through dense scrub, half a kilometre from home, with the rain soaking through my broad-brimmed hat, and running down my neck. Every so often, I stop and shout "FROG!" as loudly as I can. Then I raise my dripping hat to hear if anything answers.

It's probably reasonable to ask if these are the actions of a sane man. I say they most definitely are, but then, I know what I'm doing. Or that's my story, at any rate, and I should stress here that I'm not one of those strange compulsive froggers, people who sometimes care more for amphibians than for humans. I know I retain my sense of proportion, my sanity and my good judgement, for out there, alone in the dark, I'm still rational enough to ask myself what I'm doing out in the bush, sloshing through the dripping vegetation, with mud on my thongs, and squishing between my toes.

I live on a headland near the sea, close to a large area of bush where there are three, or possibly four species of amphibian. After steady rain, there's an equally steady seepage out of the sandy soil up on the headland for some weeks, and the frogs will get the chance to rebuild their numbers after the predations of rats, snakes, birds, other frogs, and formerly, even foxes. The foxes, though, were a mixed benefit to the frogs, for since the foxes were removed, there have been more rats in the area, and rats love a meal that croaks a bit.

The adults who survive the predators for long enough will gather near the trickling water, where they call, and then mate, scattering eggs hopefully in the water. Their tadpoles will hatch a few days later and these tiny, single-minded digestive systems with a tail will rush through a hurried childhood into premature adolescence, before they sprout legs and scramble out to join their parents on the drying land.

As a boy, I collected tadpoles once or twice in a glass jar and brought them home, but I never succeeded in growing any up to adulthood. In my own adulthood, I retained a genial interest in these animals. I learned to feed the tadpoles on lettuce, to get them to the adult stage. Most importantly, I learned to provide the emerging changelings with a rock to rest on, a way out of the water. The adults have lungs, not gills, and they'll drown if they can't scramble out of the water.

Many years ago, while working as a biology teacher, I acquired by devious means a lockable glass-fronted cupboard, designed originally for chemical storage. I bolted it to a corridor wall where passing students could look in, and I bought a narrow glass tank that would fit into the cupboard. I took many tadpoles through the full cycle over several years, but I still wasn't a compulsive frogger. I just thought it was good for students to have a small "zoo" to look at. The developing tadpoles were a major part of what happened there, along with assorted invertebrates and occasional static demonstrations, but I definitely wasn't a compulsive frogger.

Later, I moved house, and soon after, we found amphibians had joined us in our garden. We got up one rainy morning to find a frothy mass of eggs in a plastic ice cream container which lay abandoned in the undergrowth. Delighted, I dug a small pond, and transferred the eggs across. Soon after, when I had to build some new stairs and a landing into the backyard, I designed and constructed a much larger pond in the wasted space underneath the stairs. Friends thought this decision was a little eccentric, but I knew I still wasn't a compulsive frogger. Even they could see that, once I explained it to them.

Some years later, I found myself working in a museum, where I was cajoled into working on a project which involved frogs, writing, and computers. I was involved in this activity rather more as a writer and computer person, though I soon found myself getting more involved in amphibian affairs. But still I resisted the temptation to become a compulsive frogger.

I did meet some compulsive froggers, quite a few of them in fact, while I was working on the project. They were admirable people like Lothar, who one day had noticed a small population of tadpoles sharing a pool with some mosquito fish. This surprised him, for mosquito fishes are hungry little beasts which will attack most tadpoles, and eat them, working up from the tail.

Most people would have passed on to other things, but Lothar is an amateur scientist, using that term in its most praising way. He's an amateur who loves science and knowledge, and he grasped happily at this chance to do some original research. He thought about the phenomenon carefully, and concluded that these tadpoles must surely taste rather awful, or else they would long since have been eaten. A true man of science, he tried eating several raw tadpoles. They tasted vile, a discovery which could easily have waited forever to be discovered, but for the determination of this compulsive frogger.

Among others, I met Steve, who kept several pets in a tank in his office, where they were fed on meal worms, and where they responded with territorial cries, every time his phone rang. Later, I typed and proofed a frog book for Martyn, who kept a one-eyed tree frog in his workshop (it lost the other eye when a truck ran over it, but Martyn had nursed it back to health, and kept it for years). I knew I still wasn't a compulsive frogger, not by any of the rational standards I could construct.

You see, by now I was well-placed to judge things. The city of Sydney is home to a robust band of men and women who can identify an amphibian species from a single muffled grunt, heard from a rolling train through closed windows in the midst of a howling gale, and I'd seen many of them in action. These folk are the compulsive froggers, and I simply don't match up to their standards.

Then I moved house again. Soon after we settled into our new home, we started to notice croaking neighbours living in the bush around our house. I bought tapes to identify them, for you "earball" frogs rather than eyeballing them, and I started to learn how to provoke certain species to call, by playing tapes back to them. Then one day I found a small toadlet in my front yard, and did a quick double-take. With delight, I realised that the seepage drain near my front gate was home, or shelter at the very least, to a somewhat endangered species, a Red-crowned Toadlet. I still wasn't a compulsive frogger, but now I was distinctly interested.

Since then, I've been trying to map the toadlet's distribution across the headland by going out in wet weather and listening for its distinctive call. Somebody in Canberra told me that some of the other members of this genus, especially the Corroboree Frog of the high country, will answer if a male human voice bellows "FROG!" nearby. Testing this theory is what leads me out into the wilderness on damp still nights, firing off my shouts in the dark. That and finding out just how healthy the local toadlet population is, are my motivation, but I'm still not a compulsive frogger.

My little toadlet, the one I shout to in the dark, lives in perhaps two hundred pockets of land within twenty or thirty kilometres of my home. In all likelihood, each population carries different genes, but there's no longer any gene flow between the different localities. Once, the land would have been friendlier, and the occasional adventurous toadlet might have muddled and plopped from one locality into the next, hopping from one place of shelter and welcome to the next, carrying valuable genes from pool to pool. Now homes and shops, car-parks and factories, roads and schools, churches and well-drained playing fields cover the land, offering scant comfort to any wandering amphibian who may seek to pass by. But they provide superb convenience to any number of unnatural predators.

Each of the surviving established groupsof toadlets is an isolated remnant. If any population dies out because of disease, predators, drought or simple bad luck, it won't be replaced, it cannot be replaced, by new colonists moving in.

The potential replacements cannot swim over salt water. There's no bridge for them to use to cross over the harbour, and fresh recruits can't hop over the five frog-crippling kilometres of settled ground to get to the vacant spot from the next pocket. Until the sea levels fall, each group must stand or fall on its own.

If any isolated group dies out, the group's small part of the genetic diversity dies with it. The special genes that they alone may hold are no longer available to the population as a whole. It is a simple enough principle: even the ancient Romans understood it, when they coined the phrase "Divide et impera" - divide and rule. It is a cold implacable logical law, and its operation may one day wipe out all of the toadlets.

But why should we worry about one tiny, cold and clammy creature, when there are hundreds of other amphibian species in Australia? In our society, economists set the values, looking at commodity value mostly, and then at amenity value, but there's no dollar value in morality. The toadlet's cry is unmelodious, annoying even, so why should we bother?

That question underlines the problem for many species. If we can't eat them, farm them, skin them, milk them, shear them or get useful chemicals from them, they're not a commodity. If we can't admire them, cuddle them, patronise them or simper over them, they have no amenity value. And to most people, remember, amphibians are only useful when kissed and turned into handsome princes.

In the world of cost-benefit analysis, the dollars and cents cost of retaining a species can be easily determined. But when we look only at the dollars and cents benefits which might accrue from a species in the future, or that we get now, then when the benefits prove to be less than the cost of preservation, the name of the species, in Edward Wilson's memorable phrase, is written in red ink.

Many years ago, Paul Ehrlich asked us to think of an ecosystem as being like an aeroplane, which may still be able to fly, even if you remove one or two of its components. With luck, this hypothetical aeroplane may even fly almost as well with those pieces missing, and it may even land safely. I have to suspect, though, that the airline in question might find itself under considerable pressure to set things right, to restore the missing pieces, before human life is endangered.

Economists will tell you plainly that ecosystems never threaten human life. This is a doubtful premise at best, but let's drop the analogy. I prefer to think of our local ecosystems as being like a steel bridge, the bridge the frogs need to get from one pocket to the next.

You can take out one rivet from a bridge, and nothing will happen. You can remove another rivet, and the bridge will be as steady as ever. You may even take out a few more, and still do no harm. But somewhere along the way, you'll take out one rivet too many, and the whole of the bridge will come tumbling down. Ecosystems are robust, and they can manage without some of the key species, but sooner or later, they too, will start falling apart.

Biodiversity in a species works the same way. Eliminate a few unusual genes, and no harm arises, not yet. Take a few more rare genes away, and there'll still be no problem. Sooner or later, though, one of those eliminated genes will be needed to meet some change in the environment, and the needed gene won't be there, because the gene's minders have died, and the gene has died with them.

All over Australia, the amphibians are calling "rivet, rivet", but nobody cares, not so long as the frogs' bridge is still standing. It's sagging a bit, if you look at it in the right way, and it may sway perilously from time to time, but it's still there, and that's good enough for now, for most people. Of course later, we'll survey the wreckage at the bottom of the chasm, and ask ourselves why somebody didn't do something, but by then it'll all be much too late.

It's a warm, moonless, Saturday night. It's raining, the cloud's down so low on the headland that it qualifies legally and scientifically as mist, and I'm wandering round in the dark through dense scrub, half a kilometre from home, with the rain soaking through my broad-brimmed hat, and running down my neck. Every so often, I stop and shout "FROG!" as loudly as I can. Then I raise my dripping hat to hear if anything answers.

Other nights, I've never heard the toadlet's call on this part of the headland, but now, out to my right, I hear the distinctive sound I've been straining my ears for. It's faint, it's ugly, it lacks any melodic charm, but my muddy feet and wet neck are compensated for by that single distant cry, and a feeling of joy washes over me, a great improvement on the rain.

Now I know why I'm there in the dripping mist, shouting at the night. I'm still not a compulsive frogger, but I think I understand them now.

Ockham's Razor, May 12, 1996 -- ABC Radio National.