12/10/10

How Frogs and Toads Adapt To Winter's Chill

It’s mid-December and we’re inside keeping warm, while temperatures outside are below freezing (in parts of the northern hemisphere, that is). But what about our amphibian friends? How do they survive the winter? After all, they would seem vulnerable to temperature extremes with their thin skins and need to constantly stay moist.

Actually, we don’t need to worry about the frogs. They are well-equipped to deal with the cold weather, even with Arctic temperatures.

In the fall, frogs first need to find a place to make their winter home, a living space called a hibernaculum, that will protect them from weather extremes and from predators. The frog then “sleeps” away the winter by slowing down its metabolism. When spring arrives, it wakes up and leaves the hibernaculum, ready for mating and eating.

Aquatic frogs and toads such as the leopard frog and American bullfrog usually hibernate underwater. They don’t, however, dig into the mud like turtles—turtles are able to slow down their metabolism in a much more extreme way than frogs and can get by with almost no oxygen. Aquatic frogs need more oxygen—they lie just above the mud, or only partially buried in the mud, so they are near the oxygen-rich water. They may even occasionally slowly swim around.

Terrestrial frogs and toads typically hibernate on land. Those frogs and toads that are good diggers like the American toads burrow deep into the soil, safely below the frost line. Some frogs, such as the wood frog and the spring peeper, aren’t good diggers and so must scout out their winter homes in deep cracks and crevices in logs or rocks, or they might dig down into the leaf litter.

Yet these frozen frogs aren’t dead—they have a kind of natural anti-freeze in their bodies. Ice crystals form in their organs and body cavity, but a high concentration of glucose in the frog’s vital organs prevents freezing. A partially frozen frog will stop breathing: its heart will stop beating and it will seem dead. When spring approaches and their hibernaculum warms up above freezing, the frog’s frozen body will thaw, and it will come back to life.

As you go about your holiday, all bundled up for the cold, think of the frogs with their amazing adaptations for survival, safe in their winter homes, waiting for spring.

Here’s a video from YouTube about the hibernation of a wood frog. It’s pretty amazing—take a look!

Most of the information from this post came from an article in Scientific American, How Do Frogs Survive the Winter? Why Don’t They Freeze to Death? by Rick Emmer.

12/4/10

Burned Forests Threaten the Frogs of Madagascar – Guest Post, Franco Andreone

We are so pleased that Franco Andreone, Associate Curator of Zoology, Responsible for Herpetological and Ichthyological Collections, Museo Regionale di Scienze Naturali, Torino, Italy, offered to write a guest post for Frogs Are Green about his recent visit to Madagascar and what he encountered there—the possible extinction of  frogs species due to the destruction of its forests.

______________________________________________

In October, I visited the Ankaratra, a massif next to Madagascar’s capital Antananarivo, for a quick trip in an attempt to see two of the most threatened (maybe “the most threatened”) frog species of Madagascar: Boophis williamsii and Mantidactylus pauliani.

They are both CR species and live in an area that is not yet protected and has been heavily altered. For some time, on behalf of the Amphibian Specialist Group (ASG), we have advocated the need for protecting this area. To this end, a project has been set up with the help of Conservation International and the collaboration of many colleagues, with the aim of securing the area, which is also very important because it is a draining basin for potable water for the city of Ambatolampy. Through the ASG it was also possible to get a MacArthur grant that will be helpful for any further action.

Some people, notably from the Langaha Association and Madagasikara Voakajy, have begun work on the species, along with other herp species (i.e. Furcifer campani); they have collected data on both B. williamsii and M. pauliani. The two species appear VERY localised, with no more than three spots where they have been found. M. pauliani appeared a little bit more common, but we observed less than ten B. williamsii individuals.

I was already concerned about the threats to these species and their habitat. The bad news is that during the rapid survey we did (a few hours visit), we noticed that almost ALL the exotic forest was burned. This forest, composed mainly of pines, assured a certain naturalness to the area, and prevented erosion. Now, following the voluntary burning events of last July, almost all the forest has been “transformed” into charcoal. This will have serious and terrible consequences for the human populations, especially for the availability of drinking water. Most likely, during the next rainy season there will be accelerated erosion and the water will become heavily polluted. Clearly the amphibian populations will be tragically affected as well. Although one of the sites is still within a small parcel of “natural” forest, the burned trees are all around, and at the other sites the fire event has destroyed the small residual (ferns, grass) vegetation that likely assured the survival of the species.

During the visit we found some B. williamsii, but we really wonder what the effect of the next rains will be. The tadpoles need clear and clean water, and if the water is polluted by erosion, they will most likely die.

Furthermore, there really is a risk that the species will be driven to extinction within a short time.

Boophis williamsii courtesy of Franco Andreone

Boophis williamsii tadpole courtesy of Franco Andreone

Habitat Ankaratra courtesy of Franco Andreone

Mantidactylus pauliani courtesy of Franco Andreone

For more information, please visit my website:  www.francoandreone.it

12/1/10

Become a Frog Listener and Help Save Your State's Frogs

In many parts of the country, frogs and toads have begun their hibernation, and we humans, too, are hibernating for the winter—at least in parts of the northern hemisphere. This is a good time, however, to hone your frog listening skills and to think about volunteering as a frog listener for the North American Amphibian Monitoring Program, (NAAMP) a nationwide program of the U.S. Geological Survey that studies the distribution and relative abundance of amphibians in North America. The data collected from frog listeners across the country is analyzed for patterns of amphibian stability or decline on local, regional, and national levels.

Several states are participating in this study. Georgia’s Department of Natural Resources, for example, has participated in NAAMP, since 2008. In Georgia as elsewhere, frogs serve as indicators of environmental change: the data collected by volunteers helps monitor habitat change or loss of wetlands.

In Georgia, volunteers are asked to drive a predetermined route (or routes), stopping for five minutes to listen for and report frog species and their relative abundance at 10 established wetland stops. They visit these local listening routes three times a year.

Frog listening not only helps frogs, it helps the participants, too. Listening to the frog calls, according to Sarah Barlow, a NAAMP participant, is not only relaxing and enjoyable, it also builds “a greater appreciation of being in the woods.” (Quoted in an online article Frog Listener Volunteers Answer Call To Help Survey Frogs Across Georgia.)

Before becoming a frog listener, you must first take the U.S. Geological Survey quiz and be able to idenfity 65 percent of the frogs in your state. Even if you don’t want to become a frog listener, it’s fun to take the quiz to test your knowledge of the calls of frogs in your state.

So in addition to holiday music, why not plan to listen to some other choruses—frog choruses—in preparation for spring. If you live in Georgia, you don’t have to wait that long. The first listening window next year opens January 15.

Here’s one frog from Georgia with a distinctive call, the Green Frog (Rana clamitans)

11/24/10

GREEN FRIDAY – Frog Gifts for the Holidays

Although this Friday is Black Friday, we’d like to offer an alternative: GREEN FRIDAY—a day to order some wonderful frog gifts online—no pushing and shoving at the big box stores requiredl!  Enjoy!

FROG BOOK

Frog by Thomas Marent

Frog by nature photographer Thomas Marent features over 400 truly stunning images of frogs and other amphibians. A beautifully designed and produced book (published by DK), Frog is guaranteed to turn anyone into a frog enthusiast.

FROG PUZZLE

For kids ages 9-12 (and for puzzle-loving adults) here’s a good project for a winter’s day—a 300-piece Ravensburger puzzle of colorful poison dart frogs.

FROG CALENDAR

A gorgeous mini-calendar for frog lovers.

ADOPT A FROG

Adopting a frog or other animal from the World Wildlife Fund is a great gift for a child or an adult who cares about animals.

For a $50 adoption, you will receive:

  • plush frog
  • adoption certificate
  • full-color photo of a red-eyed tree frog
  • spotlight card full of fascinating information about your frog

Ipad/Ipod Apps

If you’re planning to buy your loved one a new ipod or ipad, why not fill it with a few frog or amphibian apps! Refer to our recent post on apps.

screenshot from the FROGS! app

SAVE THE FROGS totebag:

Forget plastic bags. Do your shopping with this cool eco-friendly Save the Frogs totebag and help support a great amphibian conservation organization.

PLUSH FROG

Here’s a cute frog to cuddle with: Ty Pluffies Pond Frog

CLOTHES FOR KIDS and ADULTS

Frogs Are Green Tees

Send a positive eco-message with our It Is Easy to be Green T-shirt with art by internationally renowned illustrator Paul Zwolak. Available in kids and adult sizes. (Proceeds go to amphibian conservation organizations.)

FROG SLIPPERS

We’re not sure we can resist buying these cozy frog slippers for the women in our lives.

FROG GIFTS FOR BABY

Happy Blankies

When you buy a blanket from Happy Blankie, one is also donated to a child in need. The blankies, available in different sizes, are made with luxuriously plush “minky” dot fabric, trimmed and back with silky, charmeuse satin.

ANGEL DEAR PILLOWS, BLANKETS, AND ACCESSORIES FOR BABY

Angel dear features cashmere-soft baby blankets, rattles, clothes etc. I have the frog pillow below, which has been adopted by our new “baby” (an 8-month-old kitten) as her preferred place to nap. It is unbelievably soft and cuddly!

Frogs Are Green Onesie

Let the youngest member of your family spread the word about our amphibian friends with a Frogs Are Green Onesie. (Proceeds go to amphibian conservation organizations.)

POSTERS

This year at Frogs Are Green a couple of amazing artists have donate their work to help our cause.

Children’s book illustrator Sherry Neidigh donated her art for this lovely poster—A Frog’s Dream: Save Our Home. (Proceeds go to amphibian conservation organizations.)

Paul Zwolak donated his art for this poster —It Is Easy Being Green. (Proceeds go to amphibian conservation organizations.)


STOCKING STUFFERS

Frog key chain

My husband gave me this frog key chain, which has a button activated bright LED light and makes “Ribbet” sounds. Occasionally I bump my purse and my keychain starts ribbeting, and I enjoy seeing people’s reactions!

11/19/10

10 Frogs Handsome Enough to Kiss

While researching our post The 10 Weirdest and Most Unusual Frogs on Earth , we found so many beautiful frogs we decided to give them their own post. Below are 10 of the handsomest princes of the amphibian world.

1. Red-Eyed Tree Frog (Agalychis callidryas)

This frog might be called The Planet’s Most Beautiful Frog. It has been a pin-up on dozens of wildlife calendars and cards. But its beauty has a purpose—to help it to survive. When at rest, the frog’s eyes are closed. But if disturbed, the sudden appearance of its bright red eyes may startle a predator for a second or two—enough time for the frog to leap away. With its large toe pads and long thin limbs, it can climb trees easily. The Red-Eyed Tree Frog lives in tropical forests from southern Mexico through much of Central America. We used this frog on a poster we created to help spread awareness of the global amphibian crisis (you can download the poster for free):

Red-eyed Tree Frog from IStockPhoto.com

2. Golden toad (Bufo periglenes)

The Golden Toad became extinct 30 years after its discovery in 1976. They were found only in the Monteverde Cloud Forest Reserve of Costa Rica, where hundreds would breed in shallow forest pools. The Golden Toad has become a symbol of  the plight of frogs and toads worldwide—we don’t want other amphibians to suffer the same fate as this beautiful creature.

Golden toad, photo by Charles H. Smith, U.S. Fish and Wildlife Service

3. White’s tree frog (Litoria caerula)

These handsome frogs seem to have a perpetual smile on their faces. White’s tree frogs are often kept as pets, but they are happiest when left alone in their native home: the woodland and scrub close to water in northeast Australia and New Guinea.

courtesy of www.frognet.org

4. Strawberry poison dart frog (Dendrobates pumilio)

This frog has a bright red head and body speckled with black spots. Because of its blue legs, it is also called the Blue Jeans Frog. Like many brilliantly-colored animals, the frogs’ bright color serves as a warning—Don’t eat me or you’ll be sorry! It forages on the forest floor eating small ants and termites, from which it derives the chemicals needed to synthesize the poison. It lives in tropical rainforests of Nicaragua, Costa Rica, and Panama.

5. Ranitomeya amazonica

A recent report from the World Wildlife Fund highlighted the amazing discoveries of the past decade in the Amazonian biome. According to the report, between 1999 and 2009 more than 1,200 new species of plants and vertebrates were discovered in the Amazon – a rate of one new species every three days – confirming the Amazon as one of the most diverse places on Earth.  Ranitomeya amazonica, another beautiful poision dart frog , is one of the most extraordinary of these newly discovered species. Its main habitat is lowland moist forest near the Iquitos area in Peru.

photo copyright AFP/HO/File/Lars K

6. Malagasy Rainbow Frog (Scaphiophryne gottlebei)

One of the most beautiful of the Madagascan frogs, the Malagasy Rainbow Frog  is adapted for a burrowing lifestyle. It is able to live under the ground for up to 10 months.  But it also has claws on its forefeet to help it cling to vertical canyon walls to escape floods or predators.  Unfortunately thousands of these frogs are captured every year for the pet trade.

image from Wikipedia, by Franco Andreone

7. Venezuelan Glass Frog (Cochranella helenae)

This lovely frog, native to the subtropical or tropical most lowland forests and rivers of Venezuela has translucent skin, to help hide it among the leaves.

Photo by Cesar Luis Barrio Amoros, courtesy of Amphibian Ark

8. Tiger frog (Hyloscritus tigrinis)

The Tiger Frog was discovered in 2007 in Southwestern Colombian. Little is known about the frog except that it is not believed to be toxic. Rather with its bright coloring, the frog seems to be mimicking other poisonous animals to deter predators. This gorgeous frog is threatened by destruction of the forests where it lives.

photo copyright Francisco Jose Lopez-Lopez, courtesy of www.arkive.org

9. Harlequin frogs (Atelopus varius)

Harlequin frogs are usually black or brown with spots or streaks that can be a combination of yellow, orange, red, blue, or green.  They live in the moist, tropical forests in Central and southwestern South America. About two-thirds of over 110 species of these brightly-colored frogs have vanished since the 1980s. Their decline is attributed to the destruction of their native forests, collection by the pet trade, and fungal infection (chytrid fungus).

image copyright Forrest Bren for the New York Times

10. Wood Frog (Rana sylvatica)

The Wood Frog’s beauty is more subtle that that of its tropical cousins, yet its colors seems to mimic the color of rocks, bark, and fallen leaves in the forests in which it lives.  This frog is America’s most northernmost species, ranging from northeast USA to the Arctic Circle in Alaska and Canada. Wood Frogs have already begun hibernating. First they find a place under the leaf litter or in a crack in a log or rock to settle for their winter nap. They’ll slowly begin to freeze as soon as temperatures reach the freezing point. Then the frog’s blood will stop flowing, its lungs, heart and muscles will stop functioning, and ice will fill the body cavity: they will go from frog to frogsicle, until they begin to thaw in the warm temperatures of spring.

Wood frog, photo by John Rounds

Some of the information from this post came from Frogs and Toads (a Golden Guide) by Dave Showler, illustrated by Barry Croucher/Wildlife Art Ltd.

11/10/10

Bullfrogs and other Super Species – Will They Soon Dominate Our Planet?

Super species are the phenomenally successful invasive creatures—animals, plants, and microbes—that are dominating ecosystems around the globe. Feral pigs are relentlessly trampling across Europe, North America, and Australia. Jellyfish are dominating the world’s oceans, clogging fishing nets. Not to mention the invasive species that are in our own backyards:  house sparrows and eastern gray squirrels.

In Super Species: The Creatures That Will Dominate the Planet (Firefly Books, published October 2010) Garry Hamilton details the fascinating stories of the species that seem to have won the natural selection sweepstakes. Some of these super species include the European green crab, the giant African land snail, the Argentine ant, nutria, zebra mussels, the chytrid fungus, and killer algae.

One of the species he describes, the invasive American bullfrog, especially concerns us at Frogs Are Green. Hamilton contends that bullfrogs are more invasive than Australia’s notorious cane toads. The reasons are many—bullfrogs were shipped around the world for use as biological control agents, as pets, or for sport.

Frog farms have also led to their introduction to nonnative areas. In the late 1800s after gold miners out West ate their way through native frogs, entrepreneurs imported American bullfrogs from back East to satisfy the increasing demand. Eventually farming bullfrogs spread to other parts of the world as well.

As Hamilton describes it, bullfrog farming isn’t easy and many of the frogs in these “farms” were let loose. Most frogs wouldn’t have survived. But like many invasive species, bullfrogs are highly adaptable. Bullfrogs like deep, stable, non-moving aquatic habitats. This describes many human-modified environments: reservoirs, farm ponds, irrigation channels, and even garden water features.

Bullfrogs can survive through cold Ontario winters and the extreme heat of Southern U.S. summers. Female bullfrogs can produce between 6000 and 7000 eggs and as they mature, up to 25,000 eggs per clutch. As carnivorious amphibians, they prey on fish, water beetles, snails, turtles, bats, voles, ducklings, snakes, lizards, and salamanders.

Bullfrogs compete with and prey on native frogs. This is one of the contributing factors to the worldwide decline of amphibians. Bullfrogs may also be helping to spread the deadly chytrid fungus, which is devastating frog populations around the world.

Attempts to deal with invasive bullfrogs have been challenging. But scientists have found that their numbers are fewer in waterways that haven’t been altered by people. As Hamilton writes, “By changing the physical parameters of a freshwater wetland, humans also change the playing field for all life-forms in the ecosystem, and this results in a cascade of ecological readjustments.”

The answer, Hamilton contends, is not to use the old methods such as killing the frogs and draining ponds. Rather, he says that in order to save native frogs, we need to save their habitats. Altering habitats is conducive to an invasion of bullfrogs.

I had mixed feelings reading about invasive bullfrogs. I like coming across them in ponds in the woods of upstate New York (one of their original habitats), their eyes peering just above the water, as they croak a bass jug-a-rum sound. One of my favorite frog books, The Frog Book, written in 1906 by naturalist Mary Dickerson, describes the bullfrog:

If we go rowing on river, lake, pond or park lagoon,  some moonlit night late in late June, we are certain to hear the deep-toned call of the Bullfrog many times. Coming as it does at unexpected intervals  and from unexpected directions, it seems startlingly weird in the quiet of the night. For June nights are quiet. The insect orchestras are not in full swing and the frog choruses have disbanded.

During Dickerson’s time, bullfrogs were less common than other frogs. At that time, they had many natural predators to keep them in control: snakes, otters, hawks, owls, herons, and turtles, and frog farming was mainly in the future. But human intervention tipped the balance.

In Super Species, Hamilton documents the story of many species like bullfrogs in which human intervention and alterations of habitats led to an imbalance. But his tone isn’t hysterical. Some invasive species like the plant kudzu, he contends, don’t actually have much of an impact on local biodiversity despite alarmist news stories. These species may actually be creating a new biosphere from the “rubble of our own destruction.”

This review is part of Ecolibris’s  Green Books Campaign.  Today at 1:00 p.m. ET, 200 bloggers will take a stand to support books printed on recycled or FSC-certified paper by simultaneously publishing reviews of 200 such books. By turning a spotlight on books printed using environmentally-friendly paper, Ecolibris wants to raise the awareness of book buyers to this issue and to encourage them to take it into consideration when purchasing books.