It is the greatest mass extinction since the dinosaurs.  Population by population, species by species, amphibians are vanishing off the face of the Earth. Despite international alarm and a decade and a half of scientists scrambling for answers, the steady hemorrhaging of amphibians continues like a leaky faucet that cannot be fixed or a wound that will not heal.  Large scale die-offs of frogs around the world have prompted scientists to take desperate measures to try to save those frogs they can, even bathing frogs in Clorox solutions and keeping them in Tupperware boxes under carefully controlled conditions to prevent the spread of a deadly fungus. Will it ever be safe to return the frogs back to the ecosystem from which they were taken? Buy the DVD. This film premiered April 5, 2009.

Scientists are struggling to understand why frogs are dying all over the world.  And not just frogs – but also other amphibians, like toads, salamanders, newts, and caecilians.  Herpetologists are scientists who study amphibians and reptiles.  The better they understand what’s going on, the more likely they’ll be able to suggest how to help the frogs.

But everyone can be a part of the solution.  Here are some ways you can help:

Educate Yourself

Learn more about frogs at your local aquarium or zoo.  Natural history museums are also a good place to explore.  In New York City, for example, the American Museum of Natural History has an upcoming exhibit (opening May 2009) all about frogs.

The internet makes it easy to find frog news, ranging from action-oriented to more technical.  Many people have started their own frog-related websites.  Some scientists have frog blogs, like this one by Dr. Roland Knapp, a research biologist at the University of California’s Sierra Nevada Aquatic Research Laboratory.

Knapp studies the mountain yellow-legged frog.  When scientists showed that trout introduced into Sierra Nevada mountain lakes decimated the native frogs, the National Park Service, the U.S. Forest Service, and the California Department of Fish and Game joined together to remove non-native trout.

Just as the frog was recovering from trout overstocking, it was hit with the amphibian chytrid fungus.   The Center for Biological Diversity petitioned to add the yellow-legged frog to the endangered species list to protect them by law, but it remains only a candidate for now.

Keep informed about legislation that affects your local frog populations.  You can help frogs face threats like habitat destruction, global climate change and disease.

Protect the Environment

One of the most important ways to help frogs also helps humans -– taking care of the environment.

Frogs are particularly susceptible to changes in the environment.  Their usually moist skin helps their weak lungs by exchanging oxygen and carbon dioxide with their environment – both in water and out of it.   In fact, last year scientists found a frog without lungs -– it breathes only through its skin.

Over 6,300 different species of amphibians are known – and new species are still being found.  Nearly half of the species are in decline, mostly from threats to their habitat.   Frogs lose their homes to development, but they are also harmed by garbage, non-native plants and animals, and discarded chemicals.

Watch what you throw away—and where you throw it away—to keep frog habitats trash-free.  The water that ends up in storm drains, for example, often travels through forests and grasslands and dumps into wetlands – all prime frog habitat.

On the other hand, shorelines should stay naturally cluttered with the leaf litter, rocks and logs that frogs use for cover.   Frogs evolved over millions of years to fit into specific ecological niches defined by factors like temperature and water levels.   They need clean water to survive,  but they also eat—and feed—other species.

Don’t introduce non-native plants and animals. The tadpoles that hatch from frog eggs depend on finding their favorite plants to eat and hide under.   As with the stocked trout and the mountain yellow-legged frog, sometimes even one out-of-place species can disrupt an entire habitat.

The invasive species can sometimes be another frog – like African clawed frogs and American bullfrogs that were moved outside their original habitats.  The worldwide export of some frogs may even have contributed to spreading the amphibian chytrid fungus around the world.   African clawed frogs were once exported for medical uses and are now popular as pets. Bullfrog legs are exported all over the world as food, especially from Indonesia.

If you’d like to keep a frog as a pet, look for a pet dealer who propagates his or her own animals and don’t release the frog into the wild without consulting an expert to see if it will be an invasive species.

Reduce chemical use. The water table on which we depend collects a lot of the chemicals we flush down our drains or add to our lawns (PDF), despite our best efforts to treat the water.

Chemical pesticides used in industrial agriculture harm frogs.   But declines in frog populations also show us that something is wrong with the water we drink.

Dr. Tyrone Hayes is a developmental endocrinologist at the University of California, Berkeley.  He studies how pesticides both affect amphibian development and also promote reproductive cancer in humans.

The pesticide atrazine, which is found in almost every American’s drinking water, causes hormone disruptions in both frogs and humans.

“[It] doesn’t matter if you’re a frog, a dog, a cat, a hog, or a farmer,” says Hayes.  “The hormones that are disrupted—testosterone, estrogen, thyroid hormones—those are all the same hormones.”

Hayes’ laboratory plays host to several egg-producing male frogs – frogs that were exposed to doses of atrazine a third of what’s allowed in drinking water.  Hayes says the same dosage promotes human cancers.

Don’t flush medicines down the toilet. Pesticides degrade water quality, but so do drugs flushed into our environment (PDF).  The treatment plants that process our wastewater don’t always remove pharmaceutical chemicals.  Most medicines should be thrown in the trash – sometimes mixed with kitty litter or gravel.

Conserve water. The less water you use, the less has to be treated.  And the more water stays with frogs in natural environments.

Support Conservation

Give the frogs some time. If you want to be hands-on, find a local habitat preservation or citizen science monitoring program.  Or you can take part in a 24-hour BioBlitz near you.

Put your money where it counts. Many environmental organizations (such as Amphibian Ark and Partners in Amphibian and Reptile Conservation), zoos and aquariums, scientific consortiums, and countless community groups are already tackling the global frog crisis.  But there’s still a lot to do.  Donate or raise money for your favorite.

Controlling Mosquitoes Through Genetic Modification.

Mosquito. Photograph Credit: Flickr user Aesum via Creative Commons

Mosquitoes carry Dengue Fever, a serious viral infection that causes scores of deaths in Latin America and Asia. Oxitec, a British laboratory, has produced a genetically modified mosquito that cannot spread Dengue Fever. Although the modified insect has been released by the company in few countries and its effects have reduced Dengue Fever outbreaks, its introduction in Florida has spawned protest. A petition to bar the modified insects has gained 96,000 signatures so far. Oxitec officials have been unable to calm the fears of Floridians even though the mosquitos being released are sterilized males that cannot spread the disease and cannot pass on their modified genes.

More at Red Orbit.

“The Dirt: This Week in Nature” curated and written by Robert Raciti.

Endocrine Disruptive Pesticide Might Be Banned.

The pesticide Atrazine has been known to cause reversal in the gender of affected male frogs.

It is called Atrazine and it is responsible for innumerable animal deaths since its widespread use began. The chemical interferes with the endocrine system of animals and has been known to cause reversal in the gender of affected male frogs. The pesticide is used on a great variety of crops and some 80 million pounds of it are applied each year in the United States. It easily enters the atmosphere, does not degrade quickly, and is carried by snow and rain to places far from its origin. There is also some evidence that it is carcinogenic in humans. The European Union banned the stuff in 2004 and now the United States government might follow suit. The Environmental Protection Agency recently held an open meeting on the chemical and environmentalists are awaiting its decision.

More at Treehugger.

Nature’s Masons.

The New York Times reports on a tiny sea creature that is responsible for some of the significant structural features of our planet. Forams comprise some 6,000 different species of single cell organisms. Once they die, their shells become compressed into rock, such as limestone, and that in turn has been used in construction since ancient times. Forams are also useful for telling geological time. In fact, it was the sudden disappearance of forams from rock layers that led to the discovery of the asteroid impact that caused the great extinction of the Cretaceous period. Forams also are vital for locking up carbon dioxide. Planktonic forams absorb 25% of the carbon dioxide produce each year in the earth’s oceans. But even forams seems unable to keep up with the rate of acidification of the oceans and their shells are reportedly significantly thinner today than they were before the industrial revolution began.

Forams comprise some 6,000 different species of single cell organisms. Credit: OCC Biology Department - Marc Perkins (Via Flickr Creative Commons)

“The Dirt: This Week in Nature” curated and written by Robert Raciti.

A precise, fixed definition of hibernation is somewhat elusive. A common way of explaining hibernation is to call it a state of winter dormancy, a period of inactivity in which an animal will conserve energy by maintaining a lowered body temperature for most of the winter. Yet there are also creatures, such as the North American desert tortoise, that employ a comparable state of dormancy and body temperature regulation to protect themselves against extreme heat. This may be called aestivation. There is another term, however, brumation, that refers to a winter state of sluggishness in certain reptiles and amphibians, which don’t maintain a high body temperature. Body temperature, then, may be somewhat misleading as a telltale indicator of hibernation. Perhaps the best way to look at hibernation, given the circumstances, is as a set of seasonal adaptations that animals employ to survive regularly occurring periods of famine. Here is a closer look at the adaptations of five animals that face the challenges of a winter climate:

Bats

Northern bat species overwinter in caves where they can maintain a lowered body temperature that will allow them to pass the winter months, when their prey will disappear, without feeding. The choice of a cave is paramount: too warm, and the bats’ level of activity will rise, and they’ll starve; too cold and the bats will freeze or exhaust themselves, shivering to keep warm. To find the right cave, the bats must migrate — sometimes hundreds of miles. Bats from the north may fly south, while bats from the south may fly north. With experience, the bats learn which caves are best suited to winter survival — and they will return to a good cave year after year, thousands upon thousands of bats in a single cave.

Bears

Bears are often thought of as a very typical hibernating animal when, in fact, their winter behavior is quite extraordinary. In the late summer and early autumn, bears will begin to gorge on food, eating five times their usual diet to accumulate a five-inch layer of fat that will sustain them the entire winter. In the late autumn the bears will lose their appetites and seek out a potential den. Black bears make their dens in a hollow tree, under roots, beneath a pile of brush or branches. Grizzlies dig their dens into the side of a hill, covering the floor with branches and grass. Once in its dens den, a bear’s body temperature will never drop very far below normal and, though it becomes groggy, a bear is easily roused by outside disturbances. What’s so unusual is that, in spite of their nearly normal metabolism their metabolism is not nearly normal, but rather quite extraordinary, bears don’t need to drink or urinate all winter long. They survive on the thickness of their fat alone, while nitrogen, a potentially harmful metabolic waste product that humans excrete through urination, is actually recycled into protein — which helps maintain the bears’ muscle tissue, even as they are inactive all winter long! Meanwhile, the bears stay hydrated because water is not lost through urination. These and other physiological processes — such as how the bears keep their bone strength during these prolonged periods of inactivity — are currently being studied for their potential to help humans offset the negative effects of aging, osteoporosis, space travel, and the lethargy of modern day office work.

Chipmunks

Chipmunks are a kind of ground squirrel known for their enormous, expanding cheeks, which, each fall, they will fill to capacity with load upon load of seeds. The seeds are carried back to the chipmunk’s underground system of hibernation burrows, where there is a special chamber reserved for foodstuffs. Chipmunks spend most of the winter underground in a state of dormancy, their body temperatures lowered to conserve energy. Yet the chipmunks won’t hibernate all winter. By March they will be awake again for mating season, in spite of the often still-deep snow. It is then that the stash of seeds will prove essential.

Deer Mice

Deer mice range from the northern tree line in Alaska and Canada south to central Mexico, covering much of North America. They are a small species, 10 to 24 grams, roughly the size of house mice, yet they do not hibernate — somewhat surprising for a creature so tiny. Instead, they employ a series of adaptations to conserve energy. First, they build deep nests in tree holes, stumps, logs, or even cabins or other outbuildings. They also huddle together, as many as ten or more mice, to conserve heat. Deer mice are nocturnal, so during the day, they may go into torpor, a state of inactivity in which their body temperatures drop. Usually the torpor ends by late afternoon. Altogether, these three adaptations will allow a deer mouse to save up to 2.5 times the energy of a mouse that doesn’t employ these techniques.

Wood Frogs

Wood frogs can be found farther north than any other reptile or amphibian in North America, from the northeastern United States, across Canada, and into Alaska. In the winter, one of these frogs may be found underneath a pile of leaves, rock hard and cold — frozen, apparently. The frog isn’t dead, however, but engaged in a physiological process known as frost-tolerance in which as much as 65 percent of its total body water will freeze. The frog survives by not allowing ice to form in the cells themselves, which could slash and permanently damage the membranes. The frost-tolerance process is triggered by the onset of cold weather, when the frog’s fight-or-flight response releases adrenaline into the blood, which in turn, sets off a response in the frog’s liver that converts glycogen to glucose. This glucose is what prevents the actual cells from freezing while special proteins allow only the liquid within the frog to be concentrated together and frozen. Meanwhile, the frog’s breathing and heartbeat will stop — until the spring, when the frog will thaw out and resume breathing and pumping blood again. Although many amphibians survive the winter by digging down into the ground, below the frost line, three other North American frog species employ the wood frog’s method of frost-tolerance: the gray tree frog, spring peeper, and chorus frog.

Chytrid continues to move quickly, extinguishing entire frog populations in a matter of months.  Scientists have taken drastic measures to counteract it, such as evacuating frogs from the wild and sheltering them in a sterile environment.  The El Valle Amphibian Conservation Center in Central Panama, for example, houses 58 species of frogs in their facility, including the rare golden frog, which no longer exists in the wild. To date, the only chytrid-free area left in Panama is the Burbayar Forest, a thriving environment still full of healthy, unaffected frogs.

Frogs may seem small and insignificant, but their bodies may hold the key to important new discoveries in medical research.  Scientists are finding that chemical compounds found in frogs’ skins can be used to treat pain and block infections, and are even being explored as HIV treatments.  Our chances for the discovery of future medical miracles may be slipping away with the disappearance of these tiny creatures in our midst.

Their impact on the world’s ecosystems is great.  Frogs sit right in the middle of the food chain, and without them, other creatures are disappearing, too.  We are only just beginning to understand what life may be like without them.  The race is on to stem the tide – before the next frog crosses the thin, green line.

Frogs: The Thin Green Line premieres Sunday, April 5 at 8pm ET on PBS (check local listings).