Stories tagged frogs

Researchers at the University of South Florida recently found that the fungicide chlorothalonil, in the same family as DDT, killed almost 90% of the frogs exposed to it. They tested several species of frogs, and all had the same reaction. They are now testing the chemical's mortality rate for other organisms, including bees.

Feb
23
2011

We've written about freaky frogs on the Buzz Blog before, but some recent news may shed new light on our abnormal amphibians. Until recently, researchers thought that atrazine, an agricultural pesticide, was the sole cause of sexual deformities in frogs. Unfortunately, it's not so simple.
UT OH: What lurks in me waters?
UT OH: What lurks in me waters?Courtesy Mike Ostrowski

An ecologist at Yale University, David Skelly, sought to test assumptions about atrazine by studying the frequencies of frog deformity in different land types--agricultural, suburban, urban, and forested. Skelly expected to find the highest rates of deformities in agricultural areas, which would be consistent with atrazine being the main cause. Curiously, he found the highest rates of deformity in urban and suburban areas--places we wouldn't expect to find much atrazine. So what's going on?

It turns out that what makes atrazine so dangerous is that it mimics estrogen and binds to estrogen receptors in frog cells. Because estrogen impacts sexual development and function, so too does atrazine. But atrazine isn't the only estrogen-mimicking compound out there--there's a whole class of chemicals that mimic estrogens, including those found in birth control pills and plastics (BPA). And these chemicals are found in droves in cities and surburban areas--they're flushed into the sewage, but aren't filtered out during water treatment.
Birth control pills: Estradiol, a synthetic estrogen, helps prevent pregnancy in women. But much of it is excreted in urine and eventually makes its way into various water sources.
Birth control pills: Estradiol, a synthetic estrogen, helps prevent pregnancy in women. But much of it is excreted in urine and eventually makes its way into various water sources.Courtesy Ceridwen

So why do we care? Besides the fact that frogs are just awesome little creatures and important parts of their food webs, they have something in common with humans--estrogen receptors. The same chemicals that impact frogs can impact us. So how do we humans keep our sexual development and functioning intact?
BPA-free: This Sigg bottle is made from enameled aluminum, and it's an example of a BPA-free bottle.
BPA-free: This Sigg bottle is made from enameled aluminum, and it's an example of a BPA-free bottle.Courtesy Bucklesman

Skelly had a great idea to filter this stuff out of the water at the treatment plant, so that it won't get into our bodies from drinking water. He also suggested that regulatory changes would help so that when new chemicals are developed, they're scrutinized for unintended side effects. And of course, we can make choices that reduce our exposure, such as by buying BPA-free plastics, or using stainless steel and glass containers. And of course, increased awareness is always a good idea.

Do you take extra steps to avoid things like BPA? What are they?

It's Friday afternoon, so it's time for another Science Friday video. Science Friday
Science Friday
Courtesy Science Friday
"They look cuddly, but don't be fooled: red-eyed treefrogs (Agalychnis callidryas) have a secret dark side. When Michael Caldwell, of the Smithsonian Tropical Research Institute, filmed the frogs under infrared light he saw a behavior had hadn't seen before -- the frogs started vigorously shaking the branches they were sitting on. Caldwell and colleagues, including Karen Warkentin of Boston University, decode the meaning of the shakes in Current Biology this week."
Dec
14
2008

Note: original title using the term fertilizer was corrected to read atrazine
Leopard frog
Leopard frogCourtesy Heather Dietz

What is happening to our frogs?

A recent study showed that atrazine in pond water could lead to a higher population of snails, which harbor parasites that also infect frogs. For the study, Lucinda Johnson and her colleagues at UMD collected leopard frogs from 18 wetlands near St. Cloud, Minnesota. The researchers found a positive correlation between the amount of atrazine in a wetland and the number of parasites in that wetland's frogs. The parasite in question is a tiny worm called a trematode. They can have a negative effect on frog populations.

How atrazine effects frogs

More fertilizer = more pond scum (periphyton)
More periphyton (snail food) = more snails
More snails = more snail parasites (trematodes)
More trematodes = more trematode larva attacking tadpoles
Larva infested tadpoles and frogs have lower survival rates when atrazine is present

The trematode worm that infects the frogs gets passed to frog-eating birds like herons and egrets. Inside the birds, the worms develop to adulthood. The adults produce eggs that are released into water with the birds' feces. The eggs hatch, develop into larvae, and burrow into snails. After further development, they burrow their way out again and swim in search of tadpoles. They infect them, the tadpoles turn into frogs, and the cycle continues.

Learn more about atrazine and frogs

Source articleUMNews: The tadpoles tale .
Article in Nature: Agrochemicals increase trematode infections in a declining amphibian species

Jun
23
2008

How do we know that this isn't the Southern Sandhill Frog?: Because it has burrowed backwards, of course! A handsome toad, nonetheless.
How do we know that this isn't the Southern Sandhill Frog?: Because it has burrowed backwards, of course! A handsome toad, nonetheless.Courtesy phyzome
There’s big amphibian news this week. A brand new model of toad-looking frog was unveiled to the world on Friday: the Southern Sandhill Frog, of Australia’s Kalbarri sandhills.

Be sure not to confuse the Southern Sandhill Frog with the Northern Sandhill Frog, of Australia’s Kalbarri sandhills—the two have been distinct species for more than five million years, and the southern species is easily distinguished by its more “squashed in, munted face.”

Intensive linguistic research is ongoing as to just what the Aussies mean by “munted.”

A fun fact! Sandhill frogs burrow headfirst, as opposed to most Australian burrowing frogs, which burrow backwards! Talk about weird!

May
14
2008

Sing me a song oh pianofrog: Researchers are finding the a species of frogs in China sing mating songs as duets at ultrasonic frequencies.
Sing me a song oh pianofrog: Researchers are finding the a species of frogs in China sing mating songs as duets at ultrasonic frequencies.Courtesy carf
Keep your American Idol. I’ll settle to listening to Frog Idol.

Researchers in China have found that frogs in the wild there communicate with each other in a duet of musical tones made at ultrasonic frequencies that are beyond the hearing range of humans.

Specifically, they’ve recorded the mating calls between females and males. How’s this for setting the mood, the researchers found the romantic duets could most often be heard on rainy nights.

After recording the female portion of the duet, the researchers played back that recording to males kept in captivity. They responded by adding the male response – sort of a frog version of a duet between Barbra Streisand and Neil Diamond. The males also began leaping toward the source of the female songs.

Why is this so cool to know, besides prying into the romantic ways of Chinese frogs? It’s further proof that some animals have been able to adapt their hearing range to live successfully in their environment.

Being able to communicate at ultrasonic levels gives frogs a way to hear each other of the lower frequency noise caused by rushing river waters in their habit.

And just like human singers, the female frogs sing their portion of the duet at a higher frequency than the male frogs.

But the real lessons from these frogs may be applied in improving hearing aid technology. That’s the main purpose behind these researchers’ work.

Now if Budweiser could get its frogs to sing at ultrasonic frequencies, maybe it could sell even more beer!

Feb
29
2008

Frog of the year: Leap Day 2008 is also the start of the Year of the Frog, a global awareness effort to increase understanding of the threats frogs and other amphibians are facing around the globe.
Frog of the year: Leap Day 2008 is also the start of the Year of the Frog, a global awareness effort to increase understanding of the threats frogs and other amphibians are facing around the globe.Courtesy wikipedia
Leap Day (today, Feb. 29) usually gets its scientific props in regard to astronomy, phenology or maybe rare birthday-ology.

But those concerned with care for our amphibious friends are using today as the jumping off point to raise more awareness of the dangers frogs and their related species are facing today.

So Feb. 29, 2008, is also the start of the Year of the Frog. Here’s what’s happened in the past 28 years: 120 varieties of amphibians have gone extinct on our planet. Breaking that down into a yearly average, that’s about four species per year.

Even more sobering news, about half of the remaining 6,000 species croaking and sliming about are on endangered lists.

But here’s the big idea for the Year of the Frog. Researchers are hoping to develop an Amphibian Ark, a place similar to the Svalbard Global Seed Vault that opened this week in Norway, where zoo organizations would maintain populations of amphibians in a controlled environment that could eventually be released into the wild when appropriate environments get more stable.

Now isn’t that an idea we should all get jumping on?

Oct
01
2007

Well... He's pretty funny and pathetic...: But don't you think he'd be a little funnier and sadder if we could see through him?  (Photo by jepoirrer on flickr.com)
Well... He's pretty funny and pathetic...: But don't you think he'd be a little funnier and sadder if we could see through him? (Photo by jepoirrer on flickr.com)
Japanese scientists have struck the final, hilarious, and kind of yucky blow in the age-old fight to put frogs “back in their place.”

“Everyone already knows that dressing frogs up in clothing is pretty funny,” stated lead researcher Masayuki Sumida, professor at the Institute for Amphibian Biology of state-run Hiroshima University, “But a while back we started to wonder, ‘what if we went just the opposite way?’ What if we could create a completely naked frog?

“That would really show them who’s the boss,” added Sumida.

The IAB team would soon find, however, that creating a “naked” frog is much more difficult than one might assume. As it happens, merely removing the clothing that one has already put on a frog does not result in a naked frog. Instead what you end up with is simply a “frog.”

Taking the next logical step, the team attempted anesthetizing a frog, and removing its skin. This, they hoped, would overcome the amphibian’s natural defenses against nakedness. This experiment produced a suitably naked, but unfortunately “dead” frog, and, as the point of the experiment was to humiliate the creature, Sumida felt that the team must take a new direction.

For some time very little progress was made, and the team feared that the project’s funding would soon fall through, for lack of results. One night, however, a plucky young member of the research team remembered that the Japanese brown frog, or rena japonica carried two separate chromosomal slots, which, if occupied by specific recessive genes, could cause the normally dark colored frog to be born pale. Acting on a hunch, the researcher bred groups of frogs carrying the recessive genes. When a frog was finally produced that carried both sets of recessive genes, the team had their break through. This frog’s skin was so pale that it could actually be seen through (check out the picture). What’s more, the tadpoles with these genes bore similarly transparent skin, and one could “see dramatic changes of organs when tadpoles mutate into frogs.”

Sumida’s team hopes to patent this process for making see-through frogs, claiming that the creatures would make unique and invaluable study aids, or, at the very least, good conversation pieces.

The offspring of the transparent frogs share their parents’ traits. However, as an unexpected bonus insult to the frogs, by the next generation genetics seems to catch up, and the grandchildren die shortly after birth.

So where does research go from here? “It might seem like there’s not a lot more we could do to these little guys,” says a team spokesperson. “But we like to think that as long as there are frogs still around, we’re going to try and do something weird to them. Our next project? I don’t want to get too into it, but I’ll say this: glow-in-the-dark.”

Remember those freaky frogs first discovered by Minnesota schoolchildren in 1995? (Science Buzz did an exhibit about them, too, in early spring of 2005.) Pieter Johnson, an evolutionary biologist at the University of Colorado at Boulder (formerly of University of Wisconsin, Madison), has published his newest research: he says parasites called trematodes cause the missing and extra legs, and that runoff from farms and lawns fuels algae growth, which allows for larger snail populations, which means more trematodes and more deformed frogs....

Oct
02
2006


Pine Barrens Tree Frog: In this image the tympanum can be seen as the small round disk to the right of the eye. Image courtesy Bruce Means and the U.S. Fish and Wildlife Service.
Do frogs have ears?

Yes, they do, but they are different from the ears we have. Frogs do not have external ears, rather they have something called a tympanum. The tympanum are behind the eyes, and look like round disks. Some tympanum are easier to see than others. They receive sound waves for the frog just like the tympanic membrane (also known as the eardrum) does for us. Frogs not only use the tympanum to hear, but also use their lungs. The lungs help with hearing, and also protect the frog’s eardrums from the very loud noises frogs make by equalizing pressures between the inner and outer surfaces of the tympanum.

What does sublimation mean?

In physics, sublimation is the process by which a solid converts to a gas and bypasses a liquid stage in doing so. Have you ever seen dry ice? At room temperature, dry ice sublimates directly into a gas, skipping the liquid stage.

Where do Komodo Dragons live?

There are about 6,000 Komodo Dragons living in the wild. They live on the Lesser Sunda Islands in Indonesia.

What causes hiccups?

There are a variety of causes for hiccups, including eating too quickly, swallowing too much air, taking a cold drink while eating a hot meal, laughing, coughing, or drinking too much alcohol.

Hiccups are an involuntary spasm of the diaphragm, the large muscle that separates the chest cavity from the abdominal cavity. The sudden intake of air into the lungs is stopped by the glottis, which causes the “hic” sound.

Do you know how fast the Earth spins on its axis?

Well, if you figure the Earth does one full rotation on its axis about every 24 hours (23 hours, 56 minutes, and 04.09 seconds), and the Earth’s circumference is around 25,000 miles (24,901.55 miles), then it spins at roughly 1,040 miles per hour.

Illustration of the life-cycle of the Sun: Illustration courtesy Tablizer.
Illustration of the life-cycle of the Sun: Illustration courtesy Tablizer.Courtesy Tablizer
Will the sun explode?

No, but one day it will be large enough to push the Earth into a new orbit while eradicating the Earth’s atmosphere – but not for a long, long time. Our sun does not have enough mass to “go supernova” and explode. But, in about 5-6 billion years it will start becoming a red giant once it has used up its supply of hydrogen in its core and switched to fusing hydrogen in a shell outside of its core. While this is happening other processes will cause the sun to grow. Much, much later, the red dwarf will become a planetary nebula, and then a white dwarf. This is the standard stellar evolution for a star such as our sun.