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From our vantage point, as relatively large organisms, it can be easy to overlook the microcosmos, because it’s simply too small to see. It floats in front of our eyes at all times, and yet we cannot make out details until we turn to other tools.

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This episode is sponsored by 80,000 Hours. 80,000  Hours is a nonprofit that aims to help people have   a positive impact with their career.

Head to to start planning   a career that could potentially help solve  one of the world’s most pressing problems. From our vantage point, as relatively large  organisms, it can be easy to overlook the   microcosmos, because it is simply too small  to see.

It floats in front of our eyes at   all times, and yet we cannot make out  any of the details until we turn to other tools.  And then, even when we do turn to those  tools, it can be easy to overlook the   parts of the microcosmos that seem relatively  understated compared to all of the wondrous,   dramatic events that can take place. After all, if  you’ve just come from, say, watching a tardigrade   wandering through a maze of moss…you might find  something like this a bit underwhelming. There’s just some squishy dots, floating around,  not doing anything particularly noteworthy except for a few brief flashes of movement.

The movement  is so quick that you might see it and just move on to something else, like when you glimpse  a bird flying out of the corner of your eye. It captures your attention for a second,  and perhaps releases it just as quickly. But for today, because we are us, we're gonna linger on that moment and let it capture our  attention a little longer.

Because the organism you’re looking at now is a ciliate called Cyclidium, which is known for its ability to dart straight  through the microcosmos like an arrow. It’s   only a few micrometers in length, but packed  in its small body is the ability to detect   threats and quickly jump out of their reach. This is not the first time we’ve seen a very,   very fast-moving ciliate on this channel  before.

Early on, we watched as bundles of   the bell-shaped Vorticella extended  their long stalks and then rapidly   contracted those stalks into tightly-packed  spirals when other organisms got too close.  We’ve also watched a Spirostomum quickly evade  unwanted contact, pulling back and shrinking down   to get itself out of reach as quickly as possible. We can think of the vorticella and spirostomum as   doing something that’s more like flinching, a  rapid contraction that moves them away from a   potential threat, but that doesn’t necessarily  transport them to a whole new location.  It’s remarkable and requires both tremendous  force and speed. But ciliates like the cyclidium   we were watching earlier or these Halteria are  performing a very different sort of athleticism,   something, more like a long jump.

Not that they look like they should be   setting any records. Halteria are only  around 20 microns in length, and most of   the time they just kind of spin, like a kid on  a teacup ride with no concept of dizziness.  And charmingly, the halteria is  edged in cilia that swirls with it,   unfurling as it moves, and then wrapping  back inward as the organism winds down.  Halteria like to feed on bacteria, and  they reproduce quickly. So sometimes,   James, our master of microscopes, will  find thousands of them in a single drop,   another set of squishy dots  that move in and out of focus,   sometimes even obscuring the other interesting  bits that James is trying to look at.  But let’s zoom out, past the point where we can  see the defined lines of the Halteria’s cilia,   where it really is just one dot navigating a field  of debris.

And see if you can keep up with it.  Most of the time, it’s not really a challenge.  It looks like a floater in your vision,   a clear blob that just idles away. But then, seemingly out of nowhere,   it leaps across the screen and out of view,  potentially traveling as far as 100 times   its own body length in a single second. That  would be like if I, a 6 foot human being, could leap 600 feet in a second.

In response, you might say something like,   “Okay, yeah, sure Hank, but you’re a human  being. Things are different   in the microcosmos.” And yes, this is true. Things really are different in the microcosmos.

In fact, things are a lot more challenging. Organisms  like halteria are living in water, but because of   their small size, that water feels thick like  molasses. So, they have to rely on structures   like cilia to help them swim and move quickly.

But even then, most organisms only travel around   10 times their body length in a single second.  The fact that halteria and a select group of other   leaping ciliates are able to jump 100 times their  body length in that same second is incredible.  And we don’t know exactly what it is that makes these  impressive hops possible. But it does require   a lot of energy, so it makes  sense that in its off moments,   the halteria prefers to be a little more static. And there are a few other members of this elite   jumping ciliate group, like the Strombidium  you see here leaping around.

It is very impressive   that James can even keep up with them. And that of course is the point. Not to avoid James, the ciliates are not aware of him.

But the goal of this movement   is to help the ciliate be overlooked, to  ensure that predators can’t find them.  And it works. The slightest brush of a  predator’s presence sends these ciliates   into escape mode. In one experiment, researchers  set some rotifers upon a population of Halteria   and found that only around 12% of them ended up  as rotifer food.

Another leaping ciliate called   Strobilidium was even more successful at evading  capture, with only 3% of them getting eaten.  There is however one notable exception to this  predator evasion. While Halteria might be able to   escape rotifers, they have a dedicated predator  called the Actinobolina, which we’ve talked about   before. This tentacled, toxin-loaded ciliate could  go after anything it wanted.

But for some reason,   it dines exclusively on Halteria. Why? And how?   No clue.

Maybe they just got lucky to live in an  environment that was rich enough in Halteria that   through evolution, the Actinobolina was able  to learn how to sneak up on their cagey prey.  So perhaps it is not possible for them  to always be overlooked. Eventually,   someone will take a moment to appreciate them.  If they are unfortunate, it is the one predator   that has managed to find a way around their  tricks. But sometimes it’s just us, slowing down   just enough to catch a glimpse of something  so much faster… and so much smaller… than we are.

Thanks for coming on this journey with us as  we explore the unseen world that surrounds us.  And thanks again to 80,000 Hours  for sponsoring today’s episode. 80,000 Hours is a nonprofit that aims to help  people have a positive impact with their career.  The direction of your career path is  a big life decision and 80,000 hours   has a lot of free resources to help you plan  and research what options might be best for you. They’ve got fantastic, free resources including  decision-making tools, a constantly updated job   board, and even a podcast where they have in-depth  conversations with experts in the world’s most   pressing problems, and discuss what you can  do to help solve them. In one of their recent   episodes they discussed what’s being done on the  cutting edge of malaria control and treatment,   and the state of the art efforts that are going  towards trying to create a malaria-free world 80,000 Hours wants to help  you find a career that does   good in the world and all of their provided  resources are free!

They’re a non-profit,   and their only aim is to help you  find a fulfilling, high-impact career. Check out our link in the description or go  to to be sent   a free copy of their in-depth career  guide to start learning how you could   have a high-impact career. This will  also sign you up for their newsletter,   where they send updates on their research  and high impact job opportunities All of the names on the screen right now are  the names of people who decided that they   would be a reason why Journey to  the Microcosmos is able to exist   and keep making such delightful  little bits of content as this one.

So if you’re looking for someone to  thank, it’s these folks right here. And if you’re interested in becoming one,  you can go to If you want to see more from our  Master of Microscopes James Weiss,   you can check out Jam & Germs on Instagram.

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