The Suspects
So the search began. . .
As you might imagine, when three thousand kids disappear, frogs or not, there are going to be suspects. I assembled a motley crew of suspicious characters but something felt wrong. . .


It was a list long as a frog's leap
The list of suspects began to pile up quickly once I really started looking. There were plenty of witnesses but nobody wanted to commit. That left me to sort out the clues. But then again, that's what I'm good at. I'm a detective and clues are my stock in trade. Still, I have to admit even I'm stumped. I've got this list of suspects. There are gobs and gobs of clues but I can't seem to single out any one suspect. Then there's that other thing. That feeling I get every time I run that list through my head. No matter how many times I look at this list of suspects, I keep seeing my own reflection staring back. Why don't you take a look. . .


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Habitat destruction

 Habitat destruction
There are somethin' like 6 billion people in the world with three more babies born every second. They've got to live somewhere. They've got to eat something. Too bad the victim of this wild growth is the environment.
CLUE: We've lost over half the natural wetland in the United States alone--over 2 million acres.
CLUE: Frogs need water. They can't make long trips to find it, either, because of their porous skin, so they're pretty much homebodies. When their habitat is eliminated, so are they.
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End		 Acid rain Acid rain
Acid rain happens when fossil fuels like coal and oil are burned. They spit chemicals into the air that combine with stuff in the atmosphere to give us rains and snows containing nitric and sulfuric acids. These rains can make small lakes, streams, and wetlands more acidic and a whole lot less hospitable for wildlife.
CLUE: Frogs need water. Frog eggs are laid in water. Tadpoles hatch, live, and breath in water. Adults spend much of their lives hunting, mating, hiding, living and breathing in water. See a pattern developing here?
CLUE: One study found that even slightly acidic conditions may deform or kill tadpoles.
CLUE: Acidic conditions have been linked to the decline of the natterjack toad in England.
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End		 Pollution Pollution
Pollution wears many faces. There are direct sources like dumping and factory pipes, and indirect sources like pesticide run-off from farms and weed killer or motor oil from storm drains. If pollutants don't kill the frogs right away, they may affect their insides and cause problems down the road.
CLUE: Frogs absorb water through their skin. If that water is polluted, those chemicals are absorbed as well. Frog eggs are the same way.
CLUE: Pollutants from copper mines in Arizona have wiped out the nearby population of Tarahumara frogs.
CLUE: Studies have shown some pesticides (like the mosquito control chemical Methoprene) cause mutations or death in tadpoles and other amphibians in the lab.
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End		 Ozone depletion Ozone depletion
The ozone layer that protects earth and all of us from harmful ultraviolet-B rays (UV-B). The ozone layer has been broken down by man-made junk like CFCs. Ozone depletion around the globe ranges from 0 to 20%. This may not seem like much, but a loss of just 11% can result in UV-B rays climbing by almost 90%. I'm gettin' me some stock in a sunscreen company!
CLUE: Frogs have moist, porous skin and eggs with no hard shells--little protection from harmful UV rays.
CLUE: UV-B rays have been shown in labs to be harmful to plant and animal life (including humans).
CLUE: Many declining frog populations are found in mountain habitats (closer to the rays).
CLUE: These scientists from Oregon State University have shown that when the eggs of several Cascade amphibians were exposed to UV-B radiation they died more often than ones that were not exposed.
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End		 Harvest Harvest
Like frog legs? Well, they're not like chocolate turtles--they come from real frogs. And where do you think all those frogs came from that you dissected in school? While the harvest of frogs may not be as big as, say, salmon it is a world-wide industry. Frogs are also gathered and dried for use as medicines and collected as pets, research subjects and bait.
CLUE: The population of California red-legged frogs nearly collapsed due to the high demand for frog legs.
CLUE: When you cut the legs off a frogs--it dies.
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End		 Foreign invaders Exotic and introduced species
Pollution isn't the only thing we humans release into the environment. We are also responsible for a bunch of misplaced plant and animal species. Some are intentional, like bullfrogs in California, trout in western streams, and the marine toad in Australia. Some are not, riding on bundles of fruit, on ships, or escaping captivity.
CLUE: Bullfrogs introduced into California ponds to replace the disappearing red-legged frogs quickly out-competed the remaining frogs.
CLUE: Just to please sport fishermen, trout have been introduced into many previously fishless mountain streams where frogs were the top predator . Frog eggs and tadpoles fit nicely into the trout's natural diet, not to mention its mouth.
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End		 Disease and parasites
 Disease and parasites
Diseases and parasites are natural, right? Fleas are parasites. Measles and mumps are diseases. I guess once in a while a new disease or parasite can come in and do heavy damage 'cause the plants and animals aren't ready for it.
(Photo thanks to the Minnesota Pollution Control Agency)
CLUE: A protozoan (that's a small, simple life form--I didn't know, either) is infecting frogs in Panama, causing their skin to swell and preventing them from absorbing enough water.
CLUE: A freshwater bacterium is causing the legs of some western frogs to get red and puffy. This condition means the frogs immune system is kaput.
CLUE: A microscopic critter that was introduced by stocked fish, Saprolegnia ferax, is killing off amphibian eggs.
CLUE: A garter snake parasite has been blamed for some declines in the Northeast.
CLUE: A tiny parasite that lives beneath the skin of frogs and tadpoles is causing extra limbs and eyes to grow in some unfortunate frogs.
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End		 ? Natural population changes
Maybe it's not all so sinister. Maybe all of this is just natural. Maybe all this fuss about disappearing frogs is much ado about nothing.
CLUE: Some amphibian populations have been shown to change wildly from year to year.
CLUE: Few studies have shown a long term decline in amphibian populations. Maybe we don't know enough about how frog populations behave.
CLUE: The chorus frog on Isle Royale, Michigan seems to be a case of a natural local extinction.
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End		 Drought and frost Drought and frost
So droughts and floods are natural too, right? Maybe so but the way I hear it, our actions might just be changing the world climate and making them more common.
CLUE: Frogs rely heavily on water all through their lives.
CLUE: Missing or frozen water is bad news.
CLUE: One group of scientists think that a monster frost was responsible for the extinctions of a couple tropical frogs in Brazil.
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End		 Global warning Global Warming
Global warming and climate change is on everybody's mind but is it killing frogs? Well maybe not directly but it sure isn't helping. Increasing the temperature of the earth even by a few degrees can change weather patterns and rainfall. Add this stress to other factors and you've got another piece of the puzzle. Almost seems more like a clue than a suspect.
CLUE: One study suggests that El Nino and other climate phenomena may be responsible for eliminating the golden toad and harlequin frog in Costa Rica.
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A jumble of clues
So we've got habitat being destroyed all over the world--but there have also been mysterious disappearances in utterly untouched wilderness. Same goes for acid rain and other forms of pollution. UV radiation seems to be affecting mountain frogs, but not all missing frogs are from the mountains. Harvesting frogs for food and dissection takes a bite, but only from certain species--what about the gastric brooding frog or the golden toad? Foreign species are a problem some places but not everywhere. Ditto for droughts and frosts. This is a real baffler.

Maybe it's nothing
Maybe those scientists that say it's all just natural are right after all. We don't have many long-term studies of frog populations. Maybe these extinctions happen all the time but we've only just started noticing. I would love it if they were right, but too many scientists seem to agree that too many frogs are disappearing. Maybe natural population flux would explain the disappearance of a frog species here and there, but all over the globe, in almost every kind of habitat, under so many different conditions? It just doesn't feel right to this detective.

Maybe it's everything
Maybe it's not any one suspect. Maybe it's a bunch of them. Maybe it's all of them. Maybe global warming and acid rain have made some frogs weak and open to disease and parasites. Habitat destruction could have wiped out some others. Natural changes could account for a few more. Without even knowing it, all these suspects might be working together to eliminate frogs and other amphibians all over the world.

And here's the kicker--it's up to us all to stop it.
We're not just part of the problem, we're part of the solution.


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