This article is from the source 'guardian' and was first published or seen on . The next check for changes will be
You can find the current article at its original source at https://www.theguardian.com/environment/commentisfree/2025/feb/25/a-frog-their-eyes-can-detect-single-photon-of-light
The article has changed 2 times. There is an RSS feed of changes available.
Previous version
1
Next version
Version 0 | Version 1 |
---|---|
A frog: their eyes are so sensitive they can detect a single photon of light | A frog: their eyes are so sensitive they can detect a single photon of light |
(about 7 hours later) | |
Their metamorphosis seems more like a human’s than a butterfly’s – so much is visible, and awkward, whereas the butterfly forms in secret | Their metamorphosis seems more like a human’s than a butterfly’s – so much is visible, and awkward, whereas the butterfly forms in secret |
Some species of frog have eyes so sensitive to light that they can detect a single photon. To confirm this, scientists dissected a frog’s eye and removed the lens. If you dissected eyes in biology class, you may remember that a lens is extraordinarily simple and unlike other organs. It is a hard, clearish, object that comes out clean: no blood supply, no blood. It looks like a glass bead, and functions – inanimate – much like glass, and not like most things we find in our body (except maybe teeth, which function like knives). Look through the lens at the classroom around you, you will see it clearly, but upside down. | |
A frog in space, moving further and further from the sun, would eventually start to see not a shrinking star but tiny flashes of light: individual photons. This is because as the photons travel further from their source, they are spread over greater areas: they will hit a frog’s eye less and less often. | |
My grandmother had a pond full of frogs. During the holidays, we would collect tadpoles in jars and watch them grow bigger and grow limbs. Looking at them from the bottom of the jar, you could see their translucent skin, like the soft throat of an adult frog. The best stage was legs plus tail: the most awkward, the most like one of those kids’ books where the pages are split so that as you turn the top or bottom, a hybrid animal is formed. | |
The frog’s metamorphosis seems more like a human’s than a butterfly’s – maybe it is that so much is visible, and awkward, whereas the butterfly forms in secret. Perhaps it is that our memories make us amphibious: moving between memories, imagination, the past, the future and the world present around us. | |
I love their beautiful hands, especially those with tapioca pearls as fingertips, and the long, graceful thigh section of their legs: a surprise, attached to those boxy torsos. And that the old English word for frog is ‘frosc’. And Robert Gibb: “Breath / was a kind of skin, we learned, / In which they were wrapped.” | |
When I was a kid, We All Stand Together, the Paul McCartney song from the animated short film Rupert and the Frog Song would play often on TV as some sort of placeholder. I was growing up in newly democratic South Africa and it seemed to be part of that experience, the idea that if we all worked together, we could forgive the past and build something glorious. The song was released in 1984 – when a kids’ song backed by fictional frogs could reach No 3 on the UK singles chart – so I have no idea what it was doing on South African television a decade later. There is probably a more mundane reason than the fact that it is just totally wonderful. | |
In the film, the song starts with a frog conductor and a frog orchestra and three frog vocalists in a pink seashell. More frogs appear; they hop as they sing. They drift past, singing, on a spinning lily pad. There are frog violinists, accordion players, ballet dancers. Two black cats try to sing and are shushed by an owl. Night falls, fireflies appear, the frog animation becomes impressionistic colours and shapes; watching it now, knowing about frog eyes as I do, it seems like a film partly about this ability of frogs to register the pulse of a single quantum of light. | In the film, the song starts with a frog conductor and a frog orchestra and three frog vocalists in a pink seashell. More frogs appear; they hop as they sing. They drift past, singing, on a spinning lily pad. There are frog violinists, accordion players, ballet dancers. Two black cats try to sing and are shushed by an owl. Night falls, fireflies appear, the frog animation becomes impressionistic colours and shapes; watching it now, knowing about frog eyes as I do, it seems like a film partly about this ability of frogs to register the pulse of a single quantum of light. |
In the poet C Dale Young’s The Tree Frog, he wonders how it is that he can visualise the face of a man who is not there. “Why his image persists … is beyond anything I can understand.” | In the poet C Dale Young’s The Tree Frog, he wonders how it is that he can visualise the face of a man who is not there. “Why his image persists … is beyond anything I can understand.” |
I feel the same way: I cannot begin to understand where or how it is that I can see my bedside light switched on, and the mood of the room around it. Or myself as a child, watching frogs sing on TV. It is a trick of the light. But then you can hear nonexistent frogs, too. My grandmother is dead, but I can hear her voice, ice moving in her glass of whisky, the frogs in the dark garden outside the spare room window. | I feel the same way: I cannot begin to understand where or how it is that I can see my bedside light switched on, and the mood of the room around it. Or myself as a child, watching frogs sing on TV. It is a trick of the light. But then you can hear nonexistent frogs, too. My grandmother is dead, but I can hear her voice, ice moving in her glass of whisky, the frogs in the dark garden outside the spare room window. |
“What lessons must be learned to overcome the final act of longing?” Young asks. | “What lessons must be learned to overcome the final act of longing?” Young asks. |
Sometimes the curtain does not | Sometimes the curtain does not |
completely fall, and the play, barely visible, | completely fall, and the play, barely visible, |
continues. This much I know. This much | continues. This much I know. This much |
the textbooks have taught us. The blind man | the textbooks have taught us. The blind man |
Cervantes built continued to see and saw far | Cervantes built continued to see and saw far |
too much, could not accept the utter purity | too much, could not accept the utter purity |
of Abstraction. But is that not our essential fault? | of Abstraction. But is that not our essential fault? |
A tree frog croaks against the backdrop of memory, | A tree frog croaks against the backdrop of memory, |
and the cold sheets and darkened room return, | and the cold sheets and darkened room return, |
but you are not here to whisper me to sleep. | but you are not here to whisper me to sleep. |
Helen Sullivan is a Guardian journalist. She is writing a book for Scribner Australia | Helen Sullivan is a Guardian journalist. She is writing a book for Scribner Australia |
Do you have an animal, insect or other subject you’d like to see profiled by this columnist? Email helen.sullivan@theguardian.com | Do you have an animal, insect or other subject you’d like to see profiled by this columnist? Email helen.sullivan@theguardian.com |
Helen Sullivan is a Guardian journalist. She is writing a book for Scribner Australia | Helen Sullivan is a Guardian journalist. She is writing a book for Scribner Australia |
Do you have an animal, insect or other subject you’d like to see profiled by this columnist? Email helen.sullivan@theguardian.com | Do you have an animal, insect or other subject you’d like to see profiled by this columnist? Email helen.sullivan@theguardian.com |
Previous version
1
Next version