This story is incredible, I’m fascinated by every aspect of it:
- What decision-making process led to the idea of injecting human urine into a frog in the first place?
- How did the frogs escape? What kind of living and handling conditions are we talking about here?
- Did the bacteria that the government was concerned about make the frogs more susceptible to cold, thus the coincidental die-off at the same time as eradication was to begin?
- Will Welsh clawed frogs be the next species that we thought were gone but had just become better hidden?
I crave a one-hour documentary about this.
> What decision-making process led to the idea of injecting human urine into a frog in the first place?
In the 1930s, two South African researchers, Hillel Shapiro and Harry Zwarenstein,[26] students of Lancelot Hogben at the University of Cape Town, discovered that the urine from pregnant women would induce oocyte production in X. laevis within 8–12 hours of injection.
-- from https://en.wikipedia.org/wiki/African_clawed_frog#Use_in_res...
The reaction is to Human chorionic gonadotropi - basically it's a marker which tells a human's body "You are pregnant, proceed accordingly". If you've got a womb and are in a reasonable age range this almost certainly means you're pregnant, if not it's a sign something went badly wrong. So, testing whether this marker is present means you know months earlier than you might otherwise.
Presumably the frog "Make eggs now" marker is different, but not different enough to ensure this effect doesn't happen, after all ordinarily frogs wouldn't be exposed to the urine of pregnant humans.
> Will Welsh clawed frogs be the next species that we thought were gone but had just become better hidden?
This isn't a rare species. It just wasn't in Wales and now it once again isn't in Wales. So that's like how Wales also does not have kangaroos. No danger the kangaroo goes extinct, there are lots and they're pretty competitive. But there aren't any in Wales (outside maybe a Zoo?) and so the ecosystem there does not have a kangaroo shaped niche.
Speaking of the frog test, there is apparently an old expression "the rabbit died" in English to refer to someone being pregnant. The original test involved injecting urine into a rabbit, killing it after a few days, and examining it's ovaries
https://en.m.wiktionary.org/wiki/the_rabbit_died
https://en.m.wikipedia.org/wiki/Rabbit_test
The frog was an improvement since you didn't have to kill the frog (apparently they could survive the urine injection).
FWIW the rabbit always died whether you were pregnant or not :(.
I was watching M* A* S* H* with residents in a nursing home last week and Hot Lips thought she might be pregnant. The Colonel was concerned because they only had one rabbit and it was Radar's pet.
That made zero sense to me at the time.
In case anyone is worried about the rabbit :-), they ended up using Radar's pet rabbit for the pregnancy test, but removed the ovaries surgically for examination rather than killing the rabbit.
> there is apparently an old expression "the rabbit died" in English
This shows up in the Aerosmith song, "Sweet Emotion"
The rabbit died because it had to be autopsied to inspect the ovaries. Whether a woman was pregnant or not didn't determine whether the rabbit died.
What an astute reading of the text of my comment.
I reacted to:
> FWIW the rabbit always died whether you were pregnant or not :(.
It's not that an injection of urine if a pregnant woman kills the rabbit.
It's like the rabies test on the brain. We cannot look at the brain before you're dead, because the act of looking at it would kill you.
> The original test involved injecting urine into a rabbit, killing it after a few days,
I can see how this might be read in two different ways now.
He says in his comment that they inject the urine, then, a few days later, they kill the rabbit.
Those weren't his words, and his actual words (which he quoted above, acknowledging their ambiguity) could be (mis)read as meaning that injecting the urine killed the rabbit a few days later, especially since he also wrote "apparently [frogs] could survive the urine injection".
I do still find it odd that injecting urine into the frog repeatedly is OK for the frog, but perhaps the volume was quite small.
The rabbit always dies :(
I always think of this short story now:
https://www.uncannymagazine.com/article/rabbit-test/
I assumed that the line "can't catch me 'cause the rabbit done died" was referring to a failure to perform the rabbit test -- the rabbit they were using for the test died before the ovaries would have a chance to enlarge, therefore it was inconclusive, therefore it couldn't be proved the singer of the song got the woman in question pregnant.
TIL, poor rabbits :(
> What decision-making process led to the idea of injecting human urine into a frog in the first place?
Hormones are basically messages sent through an animal's body to signal some change should take place. It was discovered that there was a hormone called hCG produced by the human placenta that triggers "you're pregnant" changes in the body. hCG is also present in the urine.
So if you want to detect a hormone, the idea is you inject it into an animal and see if it triggers the relevant changes (since the changes are usually internal, you generally need to kill the animal to check). So you would look for an animal that responds somehow to the hCG hormone, inject urine into it, and check for the response. Mice and rabbits were first used, but it was eventually discovered that certain species of frog that are highly sensitive to hormonal changes made for much simpler and faster testing.
IANAMD/B/? I interpret this as: hCG looks like "stop ovulation" for humans(mammals?) and "star ovulation" for frogs. Is this interpretation correct? Why the opposite direction?
Obviously an overflowing buffer
> What decision-making process led to the idea of injecting human urine into a frog in the first place?
Yeah, it makes me think of how many dumb things scientists really did. I bet, that the most of them are unknown because nothing interesting happened.
> are unknown because nothing interesting happened.
Other than the intense suffering of "research animals." Come to think of it that might be why they're kept "unknown."
"Look, I just know injecting the feces of elderly men into badgers is going to pay off. I just need one more grant to buy the seed badgers."
"After how the thing with the phlegm and the horses worked out, it's a hard no."
Urine has long been used in medical testing and treatment. The term diabetes mellitus comes from the sweet taste of patients’ urine, for instance.
Estrogen extracted from pregnant women’s urine used to be used as a supplement for menopausal women. I read recently that some doctors would overprescribe urine tests during pregnancy, bill the patient and sell the excess urine.
Later as an estrogen supplement came Premarin, which is made from pregnant mares’ urine.
I can do you perhaps as well as a one-hour documentary. The science podcast Let's Learn Everything [https://www.letslearneverything.com] had an episode on the history of the use of animals in pregnancy tests. It's fascinating. See Episode 5.
https://rabbitcavern.substack.com/p/do-frogs-know-if-youre-p...
Why is this one frog being captured over and over again?????
Statistics tells us that probably means it's the only frog of this species in the area. In fact we use a related approach to estimate true populations.
But as they admit, that's only one possible reason.
It's the only one that's not very good at hiding itself.
>- What decision-making process led to the idea of injecting human urine into a frog in the first place?
such an approach has long history - peeing on wheat is known from the times of Ancient Egypt and it was widely used in Middle Ages too
https://history.nih.gov/illustrated-histories/thin-blue-line...
"Bastard Executioner" series set in 14th century has a scene on using several objects to test urine for pregnancy on.
That’s a great read, thanks for pointing it out.
> What decision-making process led to the idea of injecting human urine into a frog in the first place?
This story is from Wales.