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317511.  Wed Apr 16, 2008 7:46 am Reply with quote

That's very good in all respects. What else can I say?

317540.  Wed Apr 16, 2008 8:41 am Reply with quote

Poison frogs

There are about 135 known species of dart-poison frogs, or poison-dart frogs or poison-arrow frogs - there is much disagreement about their number and their collective designation - and most of them are so newly studied that they don’t have scientific or common names yet.

Some poison frogs, “subjected to stress in captivity may have died from their own lethal secretions.”

The outside world first learned of poison frogs in the 1820s, in an account published by a British naval captain who’d travelled in Colombia. He described how people in the Andes kept poison frogs alive in hollow canes until needed.

They take one of the unfortunate reptiles and pass a pointed piece of wood down his throat, and out one of his legs. This torture makes the poor frog perspire very much, especially on the back, which becomes covered with white froth.

The hunters would dip or roll their arrow tips in the froth, which retained its potency for up to a year. One frog was enough for about 50 arrows.

Today, experts say, a “decline in the use of blowguns” means that frogs are no longer used for poisoning arrows. These days it’s medical researchers who are most interested in these potent substances. There’s a problem, though - frogs born in captivity don’t seem to produce the toxic secretions. Nobody’s sure why; possibly the lack of certain bacteria in the environment, or something missing from the diet, perhaps.

Scientists believe that the secretions of one frog, Phyllobates bicolor, are so toxic that 0.0000004 of an ounce is enough to kill a human.

S: “Frogs” by David Badger (Voyageur Press, 1995).

Link to the poisonous/venomous spiders/snakes

Last edited by MatC on Wed Jul 09, 2008 6:25 am; edited 1 time in total

317586.  Wed Apr 16, 2008 9:36 am Reply with quote

Crikey - link to botox / botulism.

317660.  Wed Apr 16, 2008 10:20 am Reply with quote

Incidentally, I was afraid we might not have enough material on frogs so I thought I'd copy this post of Will's over from the Future thread:
Epibatidine is a potential new painkiller derived from the toxin of Ecuadorian Poison Arrow Frogs. It is more than 100 times stronger than morphine. The test for this is the so called hot plate test. A plate is heated electrically to a scalding temperature. Rats are then dropped onto it. Rats with no painkiller immediately leap into the air. Rats with 5 microgams of epibatidine stay put. They even stay put when give an morphia antidote, because epibatidine works differently. It targets nicotine receptors on the pain pathways of the central nervous system. Unlike nicotine (or morphine), epibatidine is not addictive.

Interestingly Poison arrow frogs will not make their toxins when in captivity. 700 frogs were destroyed during the isolation of this chemical.

317715.  Wed Apr 16, 2008 10:50 am Reply with quote

Flash wrote:
Incidentally, I was afraid we might not have enough material on frogs

It is a worry. I'm already at least halfway through this frog book.

318375.  Thu Apr 17, 2008 7:12 am Reply with quote

The Glass Frog or Ghost Frog is translucent from underneath; you can see its skeleton, muscles, intestines, and organs including the beating heart.

S: “Frogs” by David Badger (Voyageur Press, 1995).

318376.  Thu Apr 17, 2008 7:13 am Reply with quote

The Pyxie Frog - properly called the African Bullfrog - is big and hungry. Some frog experts refer to it as a “walking stomach,” although it doesn't really do much walking; it buries itself up to the eyes in leafmould, and lunges at anything edible that passes.

It will eat insects, worms, small reptiles, amphibians, chickens, ducks, and small mammals. In captivity they’ve been known to binge to death on mice. A South African zoo recorded an African Bullfrog in a reptile enclosure eating 17 baby spitting cobras at one sitting.

They are attentive fathers, fiercely protecting their eggs and tadpoles from predators. On the other hand, they do also eat their own tadpoles.

S: “Frogs” by David Badger (Voyageur Press, 1995).

318411.  Thu Apr 17, 2008 8:32 am Reply with quote

Male Harlequin Frogs have a “Bidder’s organ.” If you remove their testicles this organ will grow into fully functional ovaries.

S: “Frogs” by David Badger (Voyageur Press, 1995).

318465.  Thu Apr 17, 2008 9:59 am Reply with quote

The Water-Holding Frog of Australia is able to retain large amounts of water in its body, against drought. It then buries itself in an underground cocoon. Aborigines in desert areas dug up the frogs, “placed the rear of a frog in their mouth, and squeezed water from the frog.”

When the rains come, the frogs emerge in large numbers to migrate to the water; on one occasion, the transcontinental railway was halted by the frogs migrating. The trains were squashing so many of them, that the wheels could no longer grip the rails.

S: “Frogs” by David Badger (Voyageur Press, 1995).

318485.  Thu Apr 17, 2008 10:20 am Reply with quote

The 1.25 inch-long Greenhouse Frog of North America is very unusual in its method of reproduction. It lays its eggs on land, without a protective bubble mass, and the babies hatch directly from the eggs - they don’t emerge as tadpoles.

In fact, they do go through a tadpole stage, but they do so inside the egg. When it’s ready to emerge it uses an egg tooth - as birds and reptiles do -on the edge of its snout to cut its way out. The tooth is then shed - that was its only function.

The 5mm long hatchlings “in size and actions resemble tiny fleas.”

S: “Frogs” by David Badger (Voyageur Press, 1995).

Links: Fleas

328904.  Fri May 02, 2008 8:15 am Reply with quote

From today's Science cite-track mailer:

Frogs Leap to Extinction
Caroline Ash
The causes of recently documented declines in frogs since the 1980s have been hotly debated. One vigorously promulgated hypothesis is that the decline has been triggered by climate change, which has promoted virulence in a previously saprophytic fungus. An orthogonal view is that the decline reflects the spatiotemporal spread of an invasive fungal disease. In either scenario, the fungus is Batrachochytrium dendrobatidis, which colonizes frog skin and suffocates the amphibians. The declines have been particularly noticeable among the charismatic harlequin frogs of Central and South America. Lips et al. have developed a technique to analyze the unavoidably incomplete frog census data (due to infrequent sampling, remote habitats, and sociopolitical challenges) and see wavelike progressions of population falloffs that look very much like the spread of an invasive pathogen originating from three source locales. They categorically found no relation with climate change; indeed, the fungus does best at altitudes where conditions are cool and moist.

S: PloS Biol. 6, e72 (2008).

334400.  Mon May 12, 2008 5:01 am Reply with quote

MatC wrote:
When you hear a frog in the background of a Hollywood film, you are almost certainly hearing the Pacific Tree Frog - because it’s the only American species which produces the archetypal “ribbit” sound. No matter where the film is set, no matter how out-of-place the sound might be, “ever since the days of the first talking pictures” film-makers have used the Pacific Tree Frog’s voice.
S: “Frogs” by David Badger (Voyageur Press, 1995).
Links: Films, Fakes

Interestingly, whenever you see a man in a bumblebee suit (like John Belushi) I reckon they are dressed as the White-Tailed Bumblebee (Bombus lucorum).

S: Own observations.

347308.  Thu May 29, 2008 8:31 am Reply with quote

Are we too late for frogs now? post 346520 has a link to a frog that has no tadpoles but gives birth to live young.

347359.  Thu May 29, 2008 9:25 am Reply with quote

Well, it doesn't really "give birth." The frogs still lay eggs, it's just that these eggs hatch into small froglets rather than tadpoles.

349044.  Sat May 31, 2008 9:16 am Reply with quote

A number of central African frogs have claws hidden entirely within their toes that can burst through their skin when they are threatened.


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