Friends of the Eagan Core Greenway



Here a Frog, There a Frog

by David Brunet

"I'm sorry I can't get excited about it," said one of my students, "but they're just frogs." He was talking about the deformed frogs that have appeared in wetlands in Minnesota and elsewhere over the past two years. He's right, they are just little two-inch leopard frogs. If there weren't so many of them with extra limbs, we wouldn't even notice. There are other "deformed" animals around us every day--six-toed cats, one-eyed flies, maybe even dyslexic cockroaches for all I know. Nature itself deals with such "freaks" very efficiently. One-eyed flies are easy targets for frogs. Five-legged frogs are a smorgasbord for big brown bass.

According to the accounts I have read, middle school students on a school field trip suddenly realized that the grass was crawling with frogs that didn't hop right. One of the children, Jeff Fish, picked up a frog and showed it to his teacher, Cindy Reinitz from the New Country charter school. She, in turn, realized that she was seeing something she should not be seeing. In an article in Popular Science (Dec 1997), Reinitz told the story of that day: "He said, 'Look - something's wrong with this.' I thought Jeff had broken the frog's leg. But then the other kids started coming up with frogs - they were everywhere, hundreds of them - and almost every one was deformed. It was bizarre.'" Within minutes every child in her class was holding up a similarly grotesque frog, so when she returned to her office, she put the news on the Internet.

Since that discovery, the ponds around Henderson, Minnesota, have become famous. It is still not clear why the frogs are deformed, some experts blaming a hole in the ozone that allows new levels of radiation reach the unprotected frogs, others blaming high populations of predators that cause deforming injuries to the frogs in their formative days, and still others blaming something in the water. Most people seem to think that the problem is in the water, but they don't agree whether it's pesticides or pH or water temperature or the residue from the breaking down of plastics. The most recent theory is that the damage is caused by flukes, miniscule parasites in the water.

If it's something in the water, should we be worried? Are we as vulnerable as frogs? After all, frogs do more than drink the water--they spend their lives in it. "I don't see how it affects human beings," argued my student. "It's not like we spend our whole lives under water."

Not spend our lives in water? Well, yes, in fact we do.

* * * * *

Water is your life. Try living without it. We humans spend our whole lives in water.

Don't stand up to quickly. You'll hear the water sloshing around inside you. Yes, the water is there inside you, too.

Do you remember being a tadpole? For nine months you swam around inside a dark, warm puddle of water, a noisy puddle that was suspended like a water balloon inside the body of a young woman. For a long time you were content with the ever present water and the darkness. But you gradually absorbed your tail and sprouted long thin fingers and toes, and you began to wish you could poke your eyes out of the water. Just your eyes.

You hadn't seen the big world yet, so you didn't know how the surface of a pond dimples with the eyes of many frogs at dusk. But you knew what to do. You had to find the surface.

One day, you did find the surface, but when you poked your eyes out a huge hand seized you and dragged you out of the puddle, and once out, you have never been able to find your way back. Perhaps the puddle is gone. Perhaps you will find another like it. Perhaps the puddle is inside of you.

Water is our life.

How does it influence our lives, to live for nine months completely submerged? Not just any nine months, but those very months when we are growing and forming and encasing brain and nerves and lungs with tissue?

If polluted waters have a negative effect on the growth of tadpoles, can we avoid a similar damage during our tadpole days? Is the water inside our mothers pure? What if she smokes or drinks? What if she stands out in the yard after spraying for mosquitoes--will the methoprene migrate to the wetland within her? What about environmental lead? If she breathes in sulfur dioxide does it find its way into her womb as acid rain?

* * * * *

Is it possible that the extra frog legs, while interesting to be sure, have been blown out of proportion by the newspapers? Are there really more deformities than usual? Do the frogs forecast effects that might happen to human beings in the near future?

Janet Byron, in the journal Pesticide & Toxic Chemical News (Dec 3, 1998) looked at pesticides, coal-ash and other possible contaminants of the deformed frogs' environment. She also considered the possibility that the frogs are suffering from loss of habitat, or from some predator. One of the experts she consulted, Wes Birge of the University of Kentucky, called frogs "sensitive environmental monitors of pollution stress," adding that if we are to understand the effects of environmental stress, "we must look at all avenues of exposure for amphibians."

In an attempt to assess the effects of methoprene, a chemical used widely in Minnesota for mosquito control, Donald Sparling of the U.S. Geological Survey's Patuxent Wildlife Research Center set up an experiment in which he sprayed six ponds with methoprene and six ponds with temephos, an organophospate pesticide.

Of the 91 frogs and tadpoles he collected from the methoprene-sprayed ponds, fourteen demonstrated deformities, Sparling said, while none of the six he collected from the temephos-sprayed ponds showed deformities. He also collected 77 frogs and tadpoles from unsprayed ponds, and discovered that only four of them were deformed. The most common deformities were missing or partially missing limbs, almost always the right hind leg.

"This suggests that something other than predation is going on," Sparling said. "I can't imagine a predator preferring a right over a left limb."

* * * * *

Once, water was the home of every living thing. Over time, single cells banded together into chains, then into complex shapes with insides and outsides, but still the water was everywhere, inside and outside. Life without water was unthinkable. Without water, it wasn't life. Eventually, the cells learned to construct a sack that would hold the water even when the organism crawled out onto the reef. Frogs are like that even today. Every single frog recapitulates the history of life itself, from single cell to tadpole to green frog sitting on the bank blinking in the sun.

Touch a frog. You can tell. The frog's skin really is a sack holding the water in. The frog may be snoozing in the sun, but the water is still in there. Without that water, there is no life.

And you, my reader--you are a sack of water, too.

* * * * *

My son and I were in the lake after a hot sauna. We waded out to our waists, and then we dove out toward the deep water, hands out before us, bodies held as streamlined as arrows. Almost in unison we swept our arms in a single strong stroke and propelled ourselves with a single leg kick, then finished our gliding and popped our heads out of the water, side by side, forty feet from where we had dived. Suddenly, I had a vision of man as a water animal. I mean, dogs swim well, but no dog could do what my son and I had just done, submerge and glide with almost no drag, like a fish. Like an otter. No, like a frog.

We swim remarkably like frogs.

* * * * *

Remember when you were a kid, at the lake, pants legs rolled up past your knees, or better yet in a pair of green shorts, trying to catch a frog? I have an image of you in my mind just like that, and you're maybe ten years old. Frogs everywhere, but in a whole afternoon, you were lucky to catch a single one. In those days, you knew this: frogs are survivors. Your height and your big brain gave you no advantage over them.

In fact, in that wet world between the land and the lake, nothing is better equipped for survival than a frog. Big round eyes on top of his head, so he can stay completely underwater except for those big peering eyeballs. Powerful hind legs clear up to his chin, to propel him out of trouble right NOW. Big webbed feet for traction in water. Camouflage skin that lets him disappear. And the ability to stay underwater forever if need be--you can't outwait a frog.

So why are they in danger if they're so well suited to survival? In his world, the frog is the master. Fish, snakes, turtles all eat a few frogs, but in the shallow, weedy world of the frog, they don't have a commanding advantage. To catch the frog, they must follow the frog through the maze of his own world. It's strictly one-on-one, and the game is played on the frog's home court.

To understand the threat to frogs, you've got to understand the heron. The heron is a professional frogger, and it is successful because it understands the frog's world in four dimensions rather than just three. While the heron is indeed in the water with the frog, on long reed-like legs, at the same time its strong toes firmly root the bird to the ground beneath the water. When the frog dives away, the heron does not follow the frog, as the fish and the turtle do. The heron moves outside of the frog's understanding of space and time, beginning its hunt not where the frog was but where the frog will be. The frog in water has no defense against the heron, using the earth as a fulcrum to travel outside the water, through space and across time to meet the frog.

Everything that seriously threatens the frog comes from outside of its watery world. The frog is victim of a physics and a chemistry that defy the rules the frog has mastered.

You, ten years old wading in your rolled-up green shorts, discovered that the frog is only vulnerable if you play by YOUR rules. A frog cannot escape a net. The frog, with its spindly front legs, is befuddled by a child with a stone.

Flee, hide, wait, live to flee again, that's all a frog needs to know. But some enemies compress life to a fragment of a second, while other wait forever. Against them, he has no defense. A frog may swim pell-mell away from the fluorescent green of spilled methyl chloride, and never know how patiently this enemy will stalk him.

So there you are again, my froggy reader. Like the frog, you and I have few enemies in our daily realm. Tigers could get us, and in fact a few of us are eaten by tigers and bears each year, but we can generally defend ourselves against those threats. Other humans pose a much greater threat, because our advantages cancel each other out.

By far the greatest threat to us enters our world from outside, as the heron enters the world of the frog. We are upended by things that do not exist naturally--radiation, chemical poisons, and the like. Our bodies are not immune to them, and neither flight nor fight will do us any good against them. They get into the water, and because we spend our whole lives in water, we are vulnerable. One only has to look at our neighbors the frogs to see how vulnerable.

Go down to the neighborhood wetland and listen to the frogs. They are telling you something. And when they stop singing their message to you, then you should get really worried.

Pure water, that's all they are. We can learn a lot from frogs.


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