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Oh, hey there, Squeaks.  Wow!  Those are some awesome glow-sticks.  I think things that glow in the dark are so cool, especially animals that glow.  When an animal glows, that's called bioluminescence.  It's a big word so let's break it down.  'Bio' means living, and 'luminescence' means light, so bioluminescence is a long word for living things that make light. 

When you think of animals that make light, the first thing that comes to mind might be fireflies or lightning bugs, and we've learned about those before, remember, Squeaks?  But there are plenty of bioluminescent animals that don't live on land.  From teeny tiny plankton to jellies and squid, the ocean is full of creatures that make light in all kinds of ways. 

Some animals will look like they're glowing, like our glow-sticks.  Others might flash brightly or even look like they're sparkling.  There are lots of animals that light up because it can be really useful, especially in the dark ocean.  Some animals will use bioluminescence to find food, like the anglerfish.  These strange looking fish can live in some of the darkest parts of the ocean, where it can be more than a kilometer deep.  There aren't too many other animals swimming around that far below the water's surface, so it can be hard to find food down there, but not for the anglerfish.  On top of its head, the anglerfish has a tiny lure that lights up to attract nearby fish.  It's a pretty unique way to catch a meal.

Sometimes, an anglerfish will even catch and eat something twice its size.  Flashing a light can also be a great strategy for animals that are trying to get away from predators that want to eat them.  That's why some types of squid will emit a bright flash of light to startle and scare away fish that might try to attack. 

There are even animals that use light to communicate with each other.  That's what the bristle worm does.  It'll use bioluminescence to figure out whether the other worms around it are males or females.   So bioluminescence is a big help fo animals trying to survive in the ocean, but how do they do it??  No matter how hard I try, I can't make my head light up like an anglerfish!

When animals light up, that's usually because there's a special reaction happening inside them.  A reaction is when two different things mix together and make something different.  It's kind of like when you mix red and blue paint together to get purple paint, except that the ingredients bioluminescent animals mix together make light.  Most animals that glow make the light themselves, though this kind of reaction, but there are some animals that steal it.

Like a fish called the midshipman fish.  Some of these fish will eat other smaller bioluminescent animals, like shrimp.  When the shrimp glow inside them, the fish lights up.  No matter how you do it, lighting up is a great way to survive in the ocean, whether you're trying to find food, communicate, or get away from something that's trying to eat you.  Glowing animals are everywhere in the ocean, from the surface to some of the deepest depth.

Talk about an amazing adaptation.  I'd love to be able to glow like some of these animals, but glow-sticks are almost as good.

Thanks for joining us.  If you want to keep learning and having fun with Squeaks and me, hit the subscribe button and we'll see you next time here at the Fort.

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