This episode is sponsored by Fabulous, the #1 self care app that helps you start building better habits.

The first 100 people who click on the link in the description will get 25% off a Fabulous subscription. Can you guess what this is?

I’ll give you a hint. It’s extinct. And it’s something that we probably would never have expected to be filming for our channel.

Which I suppose you could say is sort of the theme of today’s episode: things we never thought we’d be showing you, but here we are. And we’re going to return to this and talk about what it is. But we’ve got a lot of unseen worlds to get to first.

A while ago, James—our master of microscopes—received a package from a coral farm containing a number of exciting things for him to study under the microscope, including a beautiful brick that had been harboring all sorts of life. We’ve done a few episodes on what he found, but of course, there’s always more. So James decided to keep the brick in a saltwater tank so that he could see what else might show up.

And one day, he found what seemed like an array of tiny two-headed vases growing on the surface of the brick. These are tunicates, though they’re better known by their very adorable name: sea squirts. They get their name because they can squirt water out of their bodies when something touches them, or when they’re taken out of water.

Unfortunately, it turned out that collecting and filming sea squirts was a bit of a challenge. They’re big and fragile, which isn’t a good combination when you’re trying to put something under the microscope. But the parts that James was able to observe were still fascinating to watch.

This is the end of one of those tubes—which are called siphons—coming off the sea squirt. And inside are several algae living in symbiosis with their sea squirt home. The sea squirt has two siphons for a very simple reason: one is to take things in, and one is to take things out.

One siphon draws water into the sea squirt, allowing it to pass through the organism so that it can eat the little bits of plankton and other food traveling on that internal wave. And then, once the sea squirt is done with the water, it passes it back out through the other siphon. Unlike the sea squirt, it was pretty easy for us to record this ciliate under the microscope.

And there’s probably nothing shocking about our channel showcasing a ciliate. But we’ll get there. This ciliate is called Lepidotrachelophyllum, which is honestly a mouthful even by ciliate name standards.

And if you look around the organism, you can see a fuzzy halo. We can’t see what that halo is with our microscope, but James’ mentor Professor Genoveva Esteban has a scanning electron microscope that is able to peer into that halo. And with it, we can see thousands of tiny organic scales layering the fuzz.

James usually finds these ciliates in a pond next to his house. So again, it’s not really a surprise to see it show up here. But this…this is more surprising.

This is a Lepidotrachelophyllum. But unlike the previous ones we were watching, which have just one mouth at the tip extending and seeking food, this one has two mouths! One in each of those finger-like projections at the top of your screen.

James asked Professor Esteban about this ciliate because she’s seen countless ciliates over the course of her own microcosmos journey, some of which she even drew for our microcosmos poster that is available over at microcosmos.store. She told James that yes, among her many strange sightings, she’d actually once come across a sample filled with hundreds and hundreds of two-headed ciliates like this, though they were a different species called Uronema. So maybe one day we’ll find more of these two-headed Lepidotrachelophyllum and this will seem less shocking to us.

But for now, well, it is a strange sight. And speaking of sight, this is an eye. That’s not our smoothest transition, but in our defense, it’s hard to switch gears from a two-headed ciliate to this: a fish.

When James ventures out to waters, he brings a net with him. The goal is to gather ciliates, but you can’t just stop other creatures from entering the plankton net if that’s where they swim. So that means sometimes our master of microscopes becomes an accidental fisherman.

Ichthyology is not our strong suit, so we’re not sure what kind of fish this is. But if any of you know, feel free to tell us in the comments. Part of what we found fascinating is just how iridescent its eyes are under the desk lamp that James uses to light up more opaque creatures like this one.

Unfortunately, the journey from water to microscope isn’t great for fish. It’s difficult to extricate them from the nets. And it’s also challenging to get the environmental conditions of their new home just right.

After putting this fish back in its jar, James returned the next day and sadly found that it had died. But he decided to keep watching the fish’s eye because as grim as it is, we have to admit that it's beautiful in its iridescence. Eyes are complicated biological devices, having to transmit light that creates a usable image for us to process.

That means filtering out light that is unfocused, and that might interfere with the final image. Humans and plenty of other animals rely on melanin pigments in our eyes to absorb those unfocused bits of light. But fish eyes are iridescent because they work differently from ours.

When researchers studied zebra fish eyes, they found that the iris has a layer of guanine crystals that reflect light back instead of absorbing it. That reflective action creates the iridescent sheen while simultaneously bouncing the light in a way that makes the fish less conspicuous in its environment. And that brings us back to the beginning, to our weird extinct sample.

James has gotten plenty of strange things delivered to his house in the name of microscopy. But this is probably one of the strangest so far. This sample came from a bag of mammoth hair that he got from Siberia.

How did James come by the opportunity to receive a bag of mammoth hair? According to him, he knows a guy who knows a guy. But apparently, it’s also not that hard to find mammoth hair on the internet.

A quick search on eBay pulls up many listings of mammoth hair, though we’re not quite sure how believable their claims of authenticity are. The availability of this hair may be exciting, but it’s also the result of a warming climate, which is melting permafrost across Siberia and revealing the ancient life that once called the area home. There’s something in all of this about the fact that shifts in climate—which likely contributed to the extinction of woolly mammoths— are now revealing their remains.

But James wasn’t examining their hair to resolve questions of extinction or explore possibilities of resurrection. He was hoping to find some ciliate buried in this sample, perhaps wrapped up in a cyst that might have protected it and kept it fused to a strand of a woolly mammoth’s hair. Unfortunately, he couldn’t find a ciliate, but the search continues.

Because if he does find one, then James will have found a ciliate that might have existed when the woolly mammoth itself was wandering the earth. An ancient unseen world, unburied and revealed in a tangle of hair. Thank you for coming on this journey with us as we explore the unseen world that surrounds us.

And thank you to Fabulous for sponsoring this episode. Fabulous is an app that was created by behavioral science researchers to gently support your personal goals. Habit changing and habit building is hard.

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The first 100 people who click on the link in the description will get 25% off a Fabulous subscription. We’d also like to thank all of the people whose names are on the screen right now. These are some of our Patreon patrons who decided that they would like to give us some money every month to help this channel exist.

So thank you again to all of them, and all of you for watching and supporting this channel. If you’d like to join our patreon community, you can do so over at patreon.com/journeytomicro If you’d like to see more from our Master of Microscopes James Weiss, you can check out Jam & Germs on Instagram And if you’d like to see more from us, there’s probably a subscribe button somewhere nearby.