Roman Mars:
This is 99% Invisible. I’m Roman Mars.

Roman Mars:
We talk to a lot of architects on this show, but this week we’re talking to an engineer.

Mark Bloschock:
My name is Mark Bloschock. And I am a professional engineer in the state of Texas.

Roman Mars:
He’s like -- really from Texas.

Mark Bloschock:
Yes, yes, I’m a fourth or fifth-generation Texan. I’ve forgotten which one. But I’ve been raised in other parts of the country too, so I can talk the talk because I have been raised in the East Coast, you know.

Emmett FitzGerald:
We talked to Mark about one of the first projects that he ever worked on.

Roman Mars:
That’s producer, Emmett FitzGerald.

Emmett FitzGerald:
He had just graduated from college at the University of Houston. And he’d gotten a job in Austin with the Texas Department of Transportation.

Mark Bloschock:
And I was in my mid-twenties at the time, so 40 years ago. Though actually, I like to say four decades, it sounds like less. I was assigned to a number of things, but I ended up on the Congress Avenue Bridge, that is, the reconstruction of the Congress Avenue Bridge.

Emmett FitzGerald:
The Ann Richards Congress Avenue Bridge is just a simple concrete arch bridge that spans Lady Bird Lake in downtown Austin. The bridge was completed in 1910, but by the late 1970s, it was in need of a tune-up.

Mark Bloschock:
It was structurally deficient. And so, it was rebuilt. And more conventional, more modern, more contemporary beams were put in called box beams.

Roman Mars:
The box beams sit below the road’s surface. And they need to be spaced a certain distance apart. Mark and the other engineers decided that the gaps should be somewhere between three-quarters of an inch and an inch and a half.

Emmett FitzGerald:
And the size of that gap didn’t seem like a particularly meaningful decision, until the bats moved in. Every year in the spring, Mexican free-tailed bats migrate from Mexico to Central Texas. And they’re looking for caves or old barns or some other protected spot where they can safely hang upside down during the day. And shortly after the bridge renovation, a bunch of bats came across the new design and were like, “Hey, this has got perfectly-sized cozy crevices now.”

Mark Bloschock:
It accidentally created this perfect environment for the bats to move into.

Roman Mars:
And they did. In the years that followed the renovation, hundreds of thousands of free-tailed bats started roosting inside the bridge.

Emmett FitzGerald:
And the people of Austin lost it.

Mark Bloschock:
There was quite a bit of hysteria in Austin back then about the bats and rabies.

Roman Mars:
The local newspaper, the “Austin American Statesman,” published headlines like, “Bats Sink Teeth Into Austin.” The New York Daily News went with, “Mass Fear in the Air as Bats Invade Austin.” And as the colony continued to grow, so did the fear.

Mark Bloschock:
Folks were starting to come up with plans to exterminate the bats, to get them out of the bridge because they… everybody knew that they were dangerous and a threat to human health and safety.

Emmett FitzGerald:
The bats had just moved into their new home. And right away, it looked like they were about to get evicted or even wiped out altogether.

Roman Mars:
But someone was about to arrive in Austin to stick up for these bats, an advocate of sorts, in the court of public opinion.

Emmett FitzGerald:
He was an ambitious young ecologist who was looking for a chance to show the world not only that bats weren’t as scary and dangerous as they were cracked up to be, but that we could live harmoniously alongside them right in the middle of a city.

Roman Mars:
Enter, the Batman.

Merlin Tuttle:
Hi, I’m Merlin Tuttle, and I’ve studied bats for the last nearly 65 years.

Emmett FitzGerald:
Merlin Tuttle is one of the world’s most prominent bat scientists. And unlike a lot of people, he LOVES bats. He’s been obsessed with them since he was a teenager growing up in Tennessee.

Merlin Tuttle:
I lived just a couple of miles from a bat cave and became very fascinated with the bats.

Roman Mars:
Maybe a little too fascinated.

Merlin Tuttle:
I got so excited about bats that I forgot to go to school sometimes.

Emmett FitzGerald:
But he managed to get through high school and college and eventually made it to graduate school. During his Ph.D. research, he used to share bat caves with Tennessee moonshiners. They even gave him his nickname.

Merlin Tuttle:
The moonshiners would actually yell across to each other, “The Batman’s a coming.” They always had lookouts to make sure it wasn’t the revenuers.

Emmett FitzGerald:
Merlin finished up his doctorate. And in 1975, he took a job in Wisconsin as the curator of mammals at the Milwaukee Public Museum. But it was kind of a tough time to be a bat scientist.

Merlin Tuttle:
A public opinion poll had just shown that bats ranked just below rattlesnakes and cockroaches on public opinion. Nearly everybody knew that most, if not all, bats were rabid and would attack you.

Roman Mars:
Bats were seen as terrifying creatures of the night, little furry monsters that would suck your blood and get tangled in your hair.

Emmett FitzGerald:
And Merlin says he would regularly read articles in mainstream magazines about swarms of rabid bats attacking people.

Merlin Tuttle:
A lot of these stories bore no resemblance to reality. They were just complete fiction.

Roman Mars:
It is a fact that bats are involved in the majority of rabies cases in the United States. And that rabies is an extremely deadly disease. But there are only one or two rabies cases a year in the US. And it’s not like those people were dive-bombed out of the blue by some blood-thirsty bat.

Emmett FitzGerald:
In all likelihood, they tried to pick up a bat and they got bitten in self-defense.

Merlin Tuttle:
And if they hadn’t handled the bat, they’d have been perfectly safe.

Emmett FitzGerald:
Merlin insists that if we don’t bother bats, they won’t bother us.

Roman Mars:
And I mean, why would we bother bats? Bats are amazing.

Merlin Tuttle:
They have social systems that are strikingly similar to those of higher primates. They share information. They form long-term friendships. And they even adopt orphans. They’re really incredible.

Emmett FitzGerald:
And they’re also really important for humans. They pollinate plants like mangoes and bananas.

Merlin Tuttle:
And all those agave plants from which the entire tequila and mezcal production comes are dependent on bats for pollination. Without bats, you could lose more than a billion-dollar industry.

Roman Mars:
Bats also eat tons of bugs, including a lot of agricultural pests. By some estimates, bats save US farmers billions of dollars every year in pest control.

Emmett FitzGerald:
But in the ’70s and ’80s, as Merlin traveled the world doing his research, everywhere he went, he saw that bats were in trouble.

Merlin Tuttle:
In that research, I couldn’t help but notice that bat populations were declining at alarming rates.

Emmett FitzGerald:
Bats were losing habitat to logging and agriculture and being driven from their homes by cave explorers. And in some places, people were just slaughtering them.

Merlin Tuttle:
And as I saw that, I became more and more concerned at the rate at which people were killing these animals needlessly.

Emmett FitzGerald:
And so at a certain point, Merlin had an epiphany. He could spend his whole life studying bats, doing great science, but what good would it do if the animals that he loved were despised by everybody else?

Roman Mars:
He decided that he needed to get out of academia and devote himself to protecting these misunderstood creatures.

Emmett FitzGerald:
Which a lot of smart people thought was a dumb idea.

Merlin Tuttle:
All of my colleagues, even my best friends, thought I was stark raving mad. Bat conservation was viewed as a hopeless issue. Even the world’s biggest traditional conservation organizations wanted nothing to do with bats. They were just deemed far too hopelessly unpopular to be helped.

Emmett FitzGerald:
But Merlin pressed on. In 1982, he launched an organization called Bat Conservation International, based in Milwaukee. And he began touring the country preaching the bat gospel to anyone who would listen, including David Letterman.

DAVID LETTERMAN:
[HE HAS SPENT 20 YEARS STUDYING BATS AND FEELS THAT THEY DON’T GET THE RESPECT THEY RIGHTFULLY DESERVE. PLEASE WELCOME, DR. MERLIN TUTTLE.]

Emmett FitzGerald:
Merlin did his best, but you can hear the audience squirming in their chairs when he starts pulling out live bats.

AUDIENCE:
[WHOA.]

Emmett FitzGerald:
And at times it doesn’t feel like Letterman is taking Merlin and his bats very seriously.

DAVID LETTERMAN:
[WHAT HAVE YOU DONE TO THAT CHIHUAHUA?]

Roman Mars:
Merlin was facing an uphill battle. But in the mid-1980s, a major opportunity fell in his lap.

Merlin Tuttle:
The first time I heard about it, it was hundreds of thousands already.

Emmett FitzGerald:
Merlin got word that a giant colony of free-tailed bats had moved into a bridge in Austin, Texas and we’re causing a collective citywide freakout.

Merlin Tuttle:
We can send you a copy of a poster from the time that really tells the story. It depicts everybody fleeing in terror and the bats coming out of the bridge. People were really frightened, and they were signing petitions to have the bats eradicated. And I knew perfectly well that, that was going to be the end of my efforts if I didn’t do something about it.

Emmett FitzGerald:
And so, in that moment, Merlin made a decision that would change the direction of his life and the fate of the Austin colony. He decided to pack up his things and move to Texas.

Roman Mars:
Austin would be the new home of “Bat Conservation International” and ground zero in Merlin Tuttle’s public relations war on behalf of bats.

NEWS ANCHOR:
[ONE OF THE PRETTIEST SIGHTS IN AUSTIN, TEXAS IS THE CONGRESS STREET BRIDGE JUST BEFORE DUSK. WHAT YOU WOULD PROBABLY RATHER NOT SEE IS UNDERNEATH THE BRIDGE, THREE-QUARTERS OF A MILLION BATS HEADING OUT FOR THE NIGHT.]

Emmett FitzGerald:
This newscast is from the late ’80s, just after Merlin moved to town.

NEWS ANCHOR:
[FOR MOST OF US, THE MERE THOUGHT OF A BAT CONJURES UP NOTIONS OF DISEASE AND DISGUST. BUT THAT’S WRONG, ACCORDING TO AUSTIN-BASED BAT CONSERVATION INTERNATIONAL. MERLIN TUTTLE AND HIS STAFF CLAIMED BATS HAVE BEEN GETTING A BAD RAP FOR CENTURIES.]

Merlin Tuttle:
They’re vastly understudied, vastly underappreciated, and overly persecuted.

Roman Mars:
But at first, Merlin’s pro bat message didn’t go over too well in Austin.

Emmett FitzGerald:
The magazine “Texas Monthly” gave Merlin their infamous Bum Steer Award, a tongue-in-cheek honor typically reserved for corrupt politicians and other dubious figures. And to be fair, at the time, the idea of saving bats did seem highly dubious.

Linda Moore:
Bats, as you know, have had a bad rap.

Emmett FitzGerald:
This is Linda Moore, one of the first people Merlin hired after moving to Austin and one of his very first converts to Team Bat. Linda responded to an ad for a bookkeeping job at a quote, “conservation organization.”

Linda Moore:
I didn’t know a thing about bats, because he hadn’t mentioned that in the ad.

Emmett FitzGerald:
But it really didn’t take Merlin very long to get her on board.

Linda Moore:
I mean, he had me at the first sentence about bats. And I was just mesmerized. And he explained, “You know, part of the mission of the organization was to dispel those myths and educate people.” I thought, well, I’m all for that.

Emmett FitzGerald:
So she started keeping the books for the organization. And Linda says that despite everything working against him – the negative publicity, the false rumors, the fear of rabies – Merlin began having the same effect on other people that he’d had on her. At first, people were constantly calling the office terrified.

Linda Moore:
People were afraid. And they would call, and they would scream on the phone and all kinds of things as you can well imagine. People were like, “Oh, I went out to see those bats because they were on the news the other night. And you know, one of the… I think I got peed on. Do you think I have rabies?”

Emmett FitzGerald:
Linda says that Merlin would always calmly talk these people down.

Linda Moore:
Merlin had such a way of talking to them that by the end of the conversation, they were wanting to know how they could save these bats.

Emmett FitzGerald:
Everyone that I spoke with for this story mentioned Merlin’s almost preternatural patience. He didn’t lecture anyone about how their fears were backwards or misplaced. He just listened and then explained how important bats were.

Merlin Tuttle:
Yes, a key to my success has been that I’m not a person who is a bleeding heart animal lover who just thinks that animals have more rights than humans. The basis of all of my conservation work has been, this is what’s good for you. These animals will leave you alone if you return the favor. And once you do that, you’ll benefit greatly from them.

Roman Mars:
Merlin’s main argument was that bats were benefiting Texans by providing free pest control. He estimated that on any given summer night, the Congress Avenue bats were eating 20,000 pounds of insects, many of them agricultural pests in the farmland outside of town.

Emmett FitzGerald:
With his calm, matter-of-fact style, Merlin won over farmers and teachers and public health officials. And then the media coverage started to shift.

Roman Mars:
The “Statesman” published articles reassuring readers that the bridge colony was perfectly safe as long as people didn’t touch any bats. There was even an article celebrating Austin’s bats in “National Geographic.”

Emmett FitzGerald:
And that article actually featured pictures that Merlin had taken himself. He had picked up photography because he was tired of seeing photos that had been shot to make the bats look menacing.

Merlin Tuttle:
The straight-on shots, the bat has his mouth wide open sending out echolocation pulses, and he can look like he’s attacking. But I’ll take a three-quarter angle shot where he actually looks like he may be smiling. And it makes a huge difference to public perception. In my pictures, the bats are all smiling and just as cute as any other animal.

Roman Mars:
Merlin was convinced that people fear things they don’t know. And so he wanted to make sure people in Austin got the chance to know real bats up close, one bat in particular actually, a very cute bat called a flying fox that was brought back from a trip to Kenya. Its name was Zuri.

Emmett FitzGerald:
If you’ve ever seen one of those really big-eyed bats that looks like a puppy, maybe it was munching on a banana in a YouTube video, yeah, Zuri was one of those.

Linda Moore:
He was our media star. Merlin would take him everywhere. He was on television programs and everything else. And I must give Zuri credit because, well, he was just adorable. And you take that guy around and show him at talks and everything, and you’ve won people over.

BAT CONSERVATION INTERNATIONAL REPRESENTATIVE:
[THIS IS ZURI. AND HIS NAME IN SWAHILI MEANS BEAUTIFUL.]

Emmett FitzGerald:
In this clip, someone from Bat Conservation International is holding Zuri in front of a classroom of elementary school children. The kids initially seem pretty hesitant.

CHILD:
[DO BATS BITE HARD?]

BAT CONSERVATION INTERNATIONAL REPRESENTATIVE:
[WELL, SOME BATS HAVE SHARP TEETH BECAUSE THEY NEED SHARP TEETH. HAS ANYONE SEEN HIM TRY AND BITE?]

CHILD:
[NO.]

BAT CONSERVATION INTERNATIONAL REPRESENTATIVE:
[NO. HE’S VERY GENTLE. AND THIS IS THE WAY MOST BATS ARE NATURALLY. WHAT DO THEY FEED THEIR BABIES?]

CHILD:
[BLOOD.]

BAT CONSERVATION INTERNATIONAL REPRESENTATIVE:
[NO. THEY FEED THEIR BABIES MILK.]

Emmett FitzGerald:
Over time, the school children of Austin bought in. They even started forming little bat conservation clubs. And little by little Austin’s relationship to its bats shifted from fear to acceptance and eventually even to enthusiasm. People realized that they had been ignoring this natural spectacle that was playing out every night, a million bats flying off against the backdrop of a Texas summer sunset.

Ed Crowell:
They stream out and kind of mingle with the clouds in these waves. And it’s a pretty thing to watch.

Emmett FitzGerald:
This is Ed Crowell. He was a reporter for the “Austin American Statesman” for many years. The paper’s offices are right next to the bridge. And Ed says, that at a certain point, a few brave animal lovers started showing up at dusk to watch the bats emerge. Others joined in and by the ’90s, there was a crowd on the bridge every night.

Ed Crowell:
Every evening for six, eight months of the year that the bats were here, they’d just, people would just stand four or five deep on both sides of the sidewalk to see the bats.

BAT SPECTATOR:
[OOH.]

BAT SPECTATOR:
[WOW!]

Roman Mars:
And the city started to embrace it. Businesses cropped up offering sunset bat cruises. At a certain point, the newspaper the “Statesman,” decided to build a bat viewing area next to their office.

Ed Crowell:
People started booking hotel rooms from out of town to come see the bats as one of the things I could do in Austin. And so then the city and the mayor at the time, just, hey, this is almost like a tourist attraction.

Roman Mars:
Against all odds, Merlin Tuttle had successfully rebranded the city’s bats. In 1990, four years after Merlin moved to town, the mayor declared Austin the Bat Capital of America.

Emmett FitzGerald:
Mark Bloschock, the engineer who built the bridge, didn’t mean for any of this to happen. But he watched with interest as his very practical piece of infrastructure became home to the world’s largest urban bat colony and one of Austin’s biggest attractions. Mark gives Merlin a lot of the credit for the way the city eventually embraced its bats.

Mark Bloschock:
It really took somebody like Merlin Tuttle with his unique style of non-confrontationalism to be able to start to change the tide on how people felt about bats. He’s the type of person that makes you want to help.

Emmett FitzGerald:
In the years that followed, Mark started thinking about ways that he could help the bats. He wondered, what about all the other bridges in Texas? There must be more bat colonies out there. And so with the help of another bat scientist named Brian Keeley and funding from the state of Texas, Mark started traveling the back roads in search of bat bridges.

Mark Bloschock:
We have a number of bridges in Texas that have bat colonies. In some cases, they’re fairly large. Congress is the one that is the… that’s the hallmark. That’s the one that everybody thinks of.

Emmett FitzGerald:
But Mark and Brian found that at least 11 million bats in Texas were relying on bridges and culverts for daytime shelter. And then they expanded that study nationally and figured out that bridges and culverts were providing important habitat for bats across the country.

Roman Mars:
And so they came up with guidelines for the Texas Department of Transportation to start intentionally designing bridges to attract bats. Now, if they’re building a bridge in a place where a bat colony makes sense, they will space the box beams the way they did at Congress Avenue, between three quarters of an inch and an inch and a half apart, just how the bats like it.

Mark Bloschock:
If they find it – and they will – and they get a colony going in it, they’ll do us a good service.

Emmett FitzGerald:
And conversely, if they’re building a bridge in a place where bats and humans might get a little too close to one another…

Mark Bloschock:
We specifically will have the crevice between those two box beams… we’ll specifically have that be greater than two inches. And guess what? We’re not going to get any bats.

Emmett FitzGerald:
Mark ended up spending much of his career working to make infrastructure more bat-friendly. A while back, he won an award from the Federal Highway Administration for a culvert design. And he says that the Feds couldn’t believe that a bunch of engineers and biologists had worked together on the project, voluntarily. Biologists and engineers are not seen as natural collaborators.

Mark Bloschock:
We could be perceived on opposite sides of a spectrum with regard to this issue.

Emmett FitzGerald:
Engineers on the side of people, biologists on the side of wildlife. But Mark’s whole thing was like, “What if we’re all on the same team here?”

Mark Bloschock:
The two things can go together. It doesn’t have to just be about concrete and steel and advanced materials and stress and strain and durability and cost. There can be other things that we do that affect positively or negatively the natural environment.

Roman Mars:
Varying the width of the gaps between a few box beams might not seem like an important act, but in a way, Mark is shifting what it means to be an engineer. He’s saying, the built environment and the natural environment don’t need to be at odds with one another.

Mark Bloschock:
And probably one of the best examples that nobody could miss is the Congress Avenue Bridge, how we all work together to take it from a place of fear and loathing, if you will, to a place that’s definitely an entrenched part of the Austin culture.

Emmett FitzGerald:
Every night in the summer, people line up on the Congress Avenue Bridge. Lady Bird Lake is filled with kayaks and canoes and pontoon boats, and then right at sundown, 1.5 million bats start to trickle out of the bridge as the crowd oohs and aahs.

BAT SPECTATOR:
LOOK AT THAT. LOOK. LOOK AT THAT. KEEP YOUR EYES OPEN. YEAH, THERE YOU GO. THAT’S COOL.

Emmett FitzGerald:
They fly off downstream to begin their nightly feast. And over the course of an hour or so, the flow of bats increases until they form this snaking river in the sky that stretches for what seems like miles.

Emmett FitzGerald:
Merlin Tuttle has traveled the world to see bats in incredible wild places, but he never gets tired of a good night at the bridge.

Merlin Tuttle:
I mean, it’s just truly spectacular. It’s one of the spectacular natural events in the world. And it’s right in the middle of a city.

BAT SPECTATOR:
OH MY GOSH. THERE IS SO MANY BATS. BUT WHERE ARE THEY GOING?

BAT SPECTATOR:
OH, SO MANY BATS.

BAT SPECTATOR:
OH, THERE IS ONE.

BAT SPECTATOR:
OH MY GOD. THERE’S A LOT OF BATS…

Roman Mars:
Special thanks this week to Teresa Nichta who helped coordinate our interview with Merlin. Also, just to know that Merlin no longer works for Bat Conservation International, the organization that he founded back in the 1980s. He stepped down from his role there a few years back and founded another organization, Merlin Tuttle’s Bat Conservation.

Roman Mars:
Both of these great organizations are doing important work, including taking on one of the biggest threats facing bats today, white-nose syndrome. White-nose is a disease that has killed so many bats across North America in recent years. It is a massive issue and we couldn’t get into it for this story, but we’ll have links to where you can read more about it on our website, 99pi.org.