We don’t know why salamanders glow green in blue light. They are not bioluminescent; they don’t produce their own light, which is the sort of thing sea creatures might find useful or decorative in the ocean depths. You have to shine a light on them to get the effect. We don’t know if fellow salamanders can detect each other’s glow. Basically, we don’t know shit.
It might not mean anything. Many minerals glow spectacularly in UV light, but they probably aren’t communicating anything by it. Probably. That’s the thing. Rocks have longer stories than we do and maybe they want to tell them.
But I think it’s likely salamanders are trying to get something across, if not to us. Some of them glow all over, some glow only in spots, and most of them glow brightest from their cloacal region, a.k.a. “hoo-hoo.”
Something is fluorescent if you shine a high-energy spectrum of light on it and get a lower-energy spectrum back out, because some of its electrons get excited. (Nobody knows if electrons have a hoo-hoo, but don’t bet against it.)
One of the first people to describe fluorescence was the Father of Modern Experimental Optics, Sir David Brewster; as usual, no one knows who the mother was. Sir Brewster also invented the kaleidoscope and it became an instant hit. Bazillions of them were sold because they were considered highly entertaining in the days before TV. Naturally, Sir David didn’t get a dime off of it because he was not the kind of smart that doesn’t show off the prototype before securing the patent.
This leads me to believe we are related. Apparently we are both related to the William Brewster who herded a group of pious and nauseated folk onto the Mayflower. And when I look back into the dank-spirited and homely bunch that are my most recent ancestors, they had these things in common: smart, religious, and not liable to make any money. Sir David Brewster was born in 1781 and had the misfortune of not dying before photography was invented, and a sorrier face you won’t want to meet. He was brilliant, cranky, teetotaling, religious, and dour. He was considered a prodigy and sent to school where he did science (you could just Do Science back then) and they gave him some kind of license to preach along with his degree.
So he took to the pulpit. Once. According to a colleague, “the first day he mounted the pulpit was the last, for he had…a nervous something about him that made him swither when he heard his own voice and saw a congregation eyeing him.”
I am instantly brought back to the unfortunate day Pastor Lange talked my father into delivering a little sermon to the congregation. I don’t remember the subject except that it was about Nature, or God’s Works, if you prefer, and he was able to pull it off because he wrote beautifully and had a great command of metaphor, natural science and scripture (King James only, please), but when he got up to speak, his deep voice went thin and weird and he plucked nervously at his throat and shook visibly and looked like he was passing a stone.
Clearly he was tracking along some parallel cousin path with Sir David. My lineage is rife with intelligent, overly pious, poor, sober men with baleful faces. I would like to think that my father made that first break with the legacy by merely being smart, cranky, poor, and dour, but having a tot of sherry once a year; also, being a churchgoer but probably not a believer. Plus he actually would’ve been pretty if he smiled more.
I’m trying to complete the transformation by being even-tempered, irreverent, and a lush. My father and I were both maniacal salamander fans. He would’ve been out there in the swamps with a blue light in a heartbeat. He was not the sort of scientist who would be inclined to grind up salamanders in order to use their glowing portions in a medical device or something. He just would want to learn more about them.
Because who knows? Maybe when you shine a blue light on them, they swither.