National Geographic News
Photo of glow-in-the-dark ice cream.

Lick Me I'm Delicious's glow-in-the-dark ice cream uses a synthesized protein from jellyfish for its unique glimmer.

Photograph by Lick Me I'm Delicious

Tanya Basu

National Geographic

Published November 8, 2013

I scream, you scream, we all scream for … glow-in-the-dark ice cream?

British boutique ice cream maker Lick Me I'm Delicious (yes, that is the company's real name) recently released a glow-in-the-dark ice cream that uses a luminescent protein from glowing jellyfish. The idea? Lick the ice cream and calcium-activated proteins react by glowing, thanks to differences in your mouth's warmer pH level and the ice cream's more neutral pH.

If you're tempted to see if glow-in-the-dark ice cream merits glowing praise, be forewarned: a scoop will set you back about $220 in sweet change. Turns out jellyfish protein isn't exactly cheap. But no worries: Charlie Harry Francis, the food scientist who invented the treat, assures foodies that it's safe for consumption.

The glowing frozen dessert made us wonder about other instances of luminescence out there. Enlighten yourself with these surprising ways nature glows at night.

Sperm. Fireworks in the dark? That's what many scientists were thinking when they genetically altered male fruit flies with red and green sperm to study reproductive biology. Turns out sperm aren't just aimlessly swimming around—they actually display complex behavior that competes with rival males' sperm in the female's sperm storage tract. In other words, sexual competition is still occurring long after the sex is over. And that conclusion couldn't have been reached without a little light in the dark.

Mushrooms. Deep in the Brazilian rain forest is a 'shroom named after the verse on eternal light in Mozart's "Requiem." Researchers and explorers have effused about the starlike quality of these itty bitty fungi in the midst of the dense nighttime darkness enveloping the foliage. The otherworldly glow probably helps these mushrooms grab some dinner—with the help of a sticky gel that lines its stem. Insects fly over, get stuck, and become a meal.

Reefs. Taking a nighttime swim in the reefs of the Pacific Ocean's Solomon Islands is brilliant. Special proteins are absorbed by these reefs and then bounced off in a spectrum of neon shades. The process is called biofluorescence, and it makes for more than a light show—doctors are hoping that these infrared proteins can be used to understand the inner workings of the brain. Now that's a bright idea.

Animals. Sheep and cats have been cloned by scientists and made to glow in the dark. This isn't too far from The Hound of the Baskervilles, the Sherlock Holmes novel where (Spoiler alert!) hounds seem to glow on a desolate Scottish moor thanks to phosphorous smeared on their teeth. Researchers hope that glow-in-the-dark critters will (literally) illuminate answers to degenerative muscular disorders and other genetic diseases. And green fluorescent proteins used in studies aren't just the stuff of mad scientist dreams: it earned the inventor glowing praise and a Nobel Prize in 2008. (Related: "Glowing Animals: Beasts Shining for Science.")

Scorpions, however, are an example of animals that naturally glow in the dark. With the help of black lights, scorpions can be illuminated and glow a ghoulish green. Scientists know scorpions have an offshoot of nitrogen in their cuticles that make them glow, but the purpose remains a mystery.

And the otherwise innocent-looking millipede is an expert at defending itself by glowing. This might seem a bit counterintuitive—why would you protect yourself by making yourself bright?—but scientists think that the millipedes are using glowing as a way to defend themselves against predators in the same way many animals use coloration in daylight to subtly declare ill consequences if they get too close. The irony? The multilegged critter from California is blind.

Follow Tanya Basu on Twitter.

13 comments
jessica m
jessica m

Can someone explain exactly what "warmer" pH is? pH is described as acidic/alkaline/neutral....but warmer? Not sure what that's supposed to mean.

Brian Doherty
Brian Doherty

How cool ! I love National Geographic, thanks for passing this on Roger.

I have also joined millions of other photographers in National Geo's yourshot site. There are some amazing photos on there being shared by people from every country.      Regards Brozza.

Gwendolyn Mugliston
Gwendolyn Mugliston

I have MS and as you may know strange stuff happens in our brains from time to time.  Late last spring wrapped in my robe I went to watch the sun light the world early in the morning. I was amazed and delighted to find every friggen thing was fluorescing in the sun's light.  It was glorious! I wish it had happened again and hope it will again. It hasn't but for those minutes the world, every leaf, blade of grass was beautifully fluorescent!

Cynthia Carlson
Cynthia Carlson

More exploitation of the Earth and its animals. Not satisfied to watch the jellyfish glow, now we have to kill it and use its luminescent protein to make cow's milk (or whatever other animal's milk - more exploitation) glow and eat it. Perversion and capitalism at its finest.

Miguel Rodriguez
Miguel Rodriguez

Bioluminiscence is the production of light by organisms. The case of scorpion is not bioluminiscence, is fluorescence. A very different phenomenon.

Barbara Piper
Barbara Piper

"This isn't too far from The Hound of the Baskervilles, the Sherlock Holmes novel where (Spoiler alert!) hounds seem to glow on a desolate Scottish moor thanks to phosphorous smeared on their teeth."

 Please read the novel. The setting was Dartmoor, at the opposite end of the UK from Scotland; it was one hound, not "hounds; and the phosphorous was not smeared on the dog's teeth.

Kai Eiselein
Kai Eiselein

@Cynthia Carlson 
Your reply was made on a machine made from exploited materials, powered by electricity made from exploited  resources. I'd guess you wear clothes, also gained through exploitation, at least ride a bike, if not also own and drive a car, both of which were also made from exploited materials.
You can get off of your high horse now.

Nate Whilk
Nate Whilk

@Barbara Piper Indeed. I've seen a number of sloppy errors like this in NG online recently. Apparently this author omitted minimal research on HotB, such as reading the Wikipedia entry.

Mark N.
Mark N.

@Nate Whilk @Barbara Piper  

While they're working on their editing, perhaps they can revamp their programming.

Remember when NatGeo was the gold standard?

Alas, now it's 'Mudcats', 'Diggers', and 'Polygamy USA', etc.

I understand you have to compete, NG, but you can do better.

(And, jeez, the bills need to be paid, but WAY too many commercials!!!)

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