There’s a certain school of thought among wildlife biologists (Exhibit A) that you should eat any organism you study. Frog scientists—who study toxic frogs, mind you—have a similar habit: lick any frog you study. “Sometimes I just can’t wait till I get back to the lab to do the chemistry, and I want to get an idea if there is something nasty,” said frog scientist Valerie Clark to National Geographic. With limited equipment out in the rainforest, a taste test is the quickest way to tell whether a frog is poisonous. Most of them can’t kill a human, but the poison can make your throat burn and constrict.
While frog-licking works in a pinch out in the field, discussing how skin secretions tickle your palate isn’t going to pass the rigors of peer review. Clark’s new study used electrical stimulation to extract skin secretions from frogs and analyzed them in a mass spectrometer. Among the products: sucrose and a new bile acid called tauromantellic acid.
The concave-eared torrent frog.
Wouldn’t it be nice if we could hear each other over the low-frequency roar of jetliners and subway trains? For some rodents, bats, and marine mammals, environmental noise doesn’t normally pose a problem, as they can communicate at ultrasonic frequencies (greater than 20 kHz, just above our maximum hearing range). There are also a couple of amphibians that exhibit this trait, but in an odd twist, researchers have now learned that female concave-eared torrent frogs are deaf to the ultrasonic components of the males’ calls.
The concave-eared frog is a tree-loving native of the Huangshan Mountains in China. In choosing this woodsy area, the nocturnal amphibians must put up with one minor annoyance: streams that produce constant ambient noise. In 2006, Jun-Xian Shen, a biophysicist at the Chinese Academy of Science in Beijing, and his research team discovered that the frogs get around this sonic clutter by adding ultrasonic frequencies to their normal calls (pdf). The frogs were the first non-mammalian vertebrate found to do this, and scientists have since learned that Borneo’s hole-in-the-head frogs (yes, that’s the actual name) also chirp in ultrasonic frequencies. After finding these ultrasonic noises, researchers wanted to know what they were saying with these super-high-pitched croaks.
In 2003, DISCOVER published a profile of Tyrone Hayes, a professor of integrative biology at the University of California, Berkeley. Hayes went looking for the effects of the herbicide atrazine on frogs and found evidence that it feminized males and diminished larynxes. Apparently the professor, also know to spin rhymes at conferences, has sent years worth of emails to employees of atrazine’s manufacturer, Syngenta. The company recently released them in a 102-page pdf.
Some excerpts follow:
March 16, 2006 (page 22)
dahh… and you guys think i’m unstable?
hey, i will update you on how screwed you are tomorrow.
April 1, 2008 (page 25)
if you thought this was ever just about atrazine, you were set to lose from the beginning. not to worry… we all make mistakes… even me… I used to call you “friend”.
Apparently it’s hard to teach an old frog a new trick: landing on its legs. As painfully demonstrated in the video below, the primitive frog family Leiopelmatidae prefers to belly-flop.
We know that dim lights, a little Marvin Gaye, and a lot of red wine usually do the trick to get humans in the mood for some nookie. But what encourages endangered frogs to get it on?
Apparently, they are a fussy lot, and demand that the temperature be just right and that the humidity and day length be just so; only then will they kick off their slippers for a little bit of action. So, the Bristol Zoo obliged a few endangered frogs by building them a love shack, a specially designed “AmphiPod” with controlled natural conditions that will hopefully encourage the endangered frogs to breed.
Human parents can get into a huge lather about keeping their kids safe. So why should some species of frog be any different? Male Tungara frogs (Engystomops pustulous) will huff and puff and literally kick up a huge clump of foam that serves as a nest to shelter his mate’s eggs. The floating foam nests sound flimsy, but they’re actually incredibly durable–surviving the sun, high temperatures, infections, and parasites for four whole days until the eggs housed inside mature into tadpoles.
While scientists already knew of these foam nests, they didn’t know quite how the frogs made them. Now research (pdf) published in the Royal Society’s journal Biology Letters provides some answers. New footage filmed of an amorous pair of Tungara frogs foaming up a nest in the West Indies shows a carefully calibrated approach to nest-building that’s part yoga, part physics.
Researchers from the Charles Darwin University in Darwin, Australia (they really like Darwin there, apparently) thought they had schemed up a clever way to study how Australian Green Tree Frogs regulate their body temperature.
They surgically implanted temperature-sensitive radio transmitters inside the frogs’ bellies, but months later when they went to retrieve the frogs, the scientists found the transmitters scattered on the ground. Like so many great scientific discoveries, the researchers eventually went from “huh?” to “aha!” according to Nature News:
Researchers have discovered that these amphibians can absorb foreign objects from their body cavities into their bladders and excrete them through urination.
For the frogs, this means that any thorns or spiny insects they swallow while hopping around trees are safely (but painfully?) removed from the body.
This is the first time this phenomenon has been observed in an animal’s bladder, but some fish and snake species can absorb objects into their intestines from their body cavity and remove them by defecation.
Talk about adaptations that would make Darwin proud.
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Image: flickr / VannaGocaraRupa
We folks here at Discoblog get very excited when we hear about the discovery of new animals like the psychedelic fish.
But there’s really no place like Papua New Guinea for chance stumbling upon animals that were once mere storybook creations. On a recent six-week expedition, scientists from Oxford University, the London Zoo, and the Smithsonian Institution discovered 40 new species in a volcano that erupted 200,000 years ago. The notable finds include frogs with fangs and a Bosavi woolly rat, a rodent the size of a small cat—it’s 32.2 inches long and weighs 3.3 pounds.
“This is one of the world’s largest rats. It’s a true rat, the same kind you find in the city sewers,” said Kristofer Helgen, a biologist from the Smithsonian National Museum of Natural History, who was part of the expedition team.
Fortunately, the animals in the crater of the volcano are protected from the local hunters since the humans can’t be bothered to hike down into its center. However, the forests around the animals are anything but safe: More than 25 percent of forests in Papua New Guinea have been destroyed or damaged in the past three decades.
Image: flickr/ new species
Frogs in Scotland are being told to get a room, and for the good of the species, earth-conscious volunteers are helping them. As part of the Action Earth campaign, volunteers have constructed what they describe as an underground beehive to provide a safe place for frogs to mate, since their usual mating location—near ponds or other bodies of water—leaves them vulnerable to predators like foxes and herons.
Guests at the frog hotel, an enclosed, two-tiered space made from wood and recycled materials, are first greeted with a complimentary snack in the compost cafe, where insects and bees abound. They are then led up a ramp into the “sleeping area,” where they can, er, socialize to their hearts’ content, safe from attack and left only in the company of other frogs—up to 20 of them at a time.