Whale Earwax Holds a Hidden History of the Ocean

Subscribe and prepare to learn something you absolutely did not know existed.

In this Niche Scientists minisode of Wildly Curious, Katy Reiss dives into one of the strangest—and most important—jobs in science: whale earwax archivist.

Yes. That’s a real thing.

Certain whales build massive earwax plugs over their lifetime, adding a new layer every six months. And scientists have learned how to read those layers like tree rings—revealing a whale’s age, stress levels, exposure to pollution, and even the history of human impact on the ocean.

🐋 What whale earwax is actually made of
 📏 Why these plugs can grow over 10 inches long
 🧪 How scientists read them like biological timelines
 🌍 What they reveal about climate change, pollution, and industrialization
 📉 And why whales are basically the ocean’s canaries in a coal mine

It’s gross. It’s fascinating. And it turns out to be one of the most powerful tools we have for understanding long-term ocean health.

🎧 This episode is part of our Niche Scientists minisode series—short episodes spotlighting the wildly specific research that quietly changes how we understand the world.

Transcript

katy: [00:00:00] So this is our second week of the mini sos our third week. I'm gonna have to stop counting 'cause there's no way I can keep track of the count of all of them. So this is our second, our second mini. So we're focusing on very niche scientists and just the bizarre topics that they've chosen to study.

So mine. Alright, I like Laura. Laura, you said in yours that you picked a variety of topics. Mine is quite the variety too, but it pretty much focuses on the typical realm of things we would focus on. So my first one now, I will say there aren't too many things in the animal science world that have completely.

Bypassed my 

laura: Yeah. 

katy: to the point that, that when I finally do learn about it, it, it feels like, it almost feels like I've skipped timelines because it's so big. Like, I don't know, like I don't know how I 

laura: this? 

katy: And that's how I feel about this [00:01:00] one. Okay. So the first up niche scientist that I'm gonna talk about is, I'm gonna talk about the generalization of what they study, and then I'm gonna talk about two individuals and then why it's important.

So first up is a whale 

ear wax archivist. 

laura: Oh, 

katy: Yeah. Right?

It's like a

laura: gross. 

So

you don't even think about whales of 

even having ears. 

katy: Well, well, so here we go. So cytologists, 'cause that's citations, 

laura: Yeah. Yeah. Yeah. 

katy: Okay. Cytologists are a group of scientists who they study whales. And the groups that you know have the whales are the whales, dolphins, porpoises.

They all produce ear wax. However, whale ear wax is made of keratin and different lipids. This differs from human ear wax because human ear wax is made up of secretions from glands combined with dead skin, cells, hair, or things like that. [00:02:00] We have ear wax to mainly protect our ear from any dust, debris, or even germs of bacteria from getting into and damaging our eardrum and inner ear.

And oddly enough, a lot of sources said that earwax acts as a lubricant. So of course, that was a rabbit hole I had to jump jumped into. 'cause I was like. Wait a minute. I was like a lubricant. Well, yeah, because turns out obviously the natural movement of our jaw from eating or talking helps an aid in kind of like a conveyor belt.

You know what? Like the conveyor belt of motion up into our ears. And so having the ear wax, it lubricates, like if you think of your ears, and again, those who are watching us on YouTube will understand this because I'm making the hand motions, but it's kind of goes like this, you know what I mean? When you're talking or eating.

And so this movement helps the dust work its way out of your ear, and the ear wax serves as the lubricant for helping the stuff get out, which makes sense. But I was like, I guess [00:03:00] I just never would've been like, oh yeah, 

ear wax a lubricant. 

laura: I just wouldn't describe that. that's 

what it does either, right? Like I'd be like, oh, it evacuates dust, not lubricates dust. I'm like,

katy: yeah,

Right. Yeah. But it, but it does, but it, because it, that's, it's not the ear wax that gets it out of there. It's the movement of our jaw. But the ear wax helps make it happen faster. Like it would still eventually, probably get out, but not, not really. So anyway, yeah. There are some lucky ducks then who get to study these whale keratin lip, like these keratin, what is it?

Yeah. And different lipids. 

laura: So keratin is like proteins, lipids is fats, so it's just 

chunky. 

katy: Yes. Well, so not, not quite chunky, thank God. 'cause that would make this way worse. If it was, if these were described as chunky, I would've been done. That is one of those words that I 

can't y see. And I can't even do it with food. , I just, I can't.

So these earplugs that are made [00:04:00] of the keratins and the lipids can be. Like up a round, give or take 10 inches 

long, which is about like the size of a small baguette if you 

think about it. 

laura: Just, 

katy: Yeah, like a big one. Yeah. Or a baguette, like, because you gotta think of how big it is too. You know what I mean?

Much like the rings of a tree, for lack of better term, this ear wax. You can study that. And that's what these scientists do. So when it gets, let's just talk about the earwax here. 'cause that we gotta lay down the groundwork to understand what this even is. 'cause again, I was like, how have I missed this?

And all my studying, like how did I not know this was a thing? So when it gets to be about 10 inches long, does it just fall out? No. All right. Turns out all right, it can't fall out. 'cause things like baline whales, they don't have an open ear canal like we do. Their ear canals are sealed, which would make sense 'cause they're diving underwater.

So that plug just keeps building up for life every six months. A new layer 

laura: Oh. 

katy: it [00:05:00] can either be dark or light, depending on whether the whale is feeding or fasting. And because the canal's closed off, it just stays in there forever. And so over time these layers start to compress and harden more and more kind of like a waxy 

time capsule. 

laura: do they hear then? Like how is it not interfering with hearing? 

katy: so the older the whale and the denser the plug, the inner layers are darker and more compact. While the outer ones are newer and a little bit softer, it's like a really gross jawbreaker. Like if you think of it that way. All right. So like you were just saying, if the ear plug, 'cause it is called a plug.

It just keeps growing and getting denser. Does that mean that older whales are basically going deaf? Turns out, no. Again, how did I miss all? And whales are like one of my fa I love whales. How did I not figure this out? But anyway, whales don't hear through the canal the same way that we do. They actually pick up sounds through vibrations and they are a [00:06:00] lower jawbone.

Yeah. Which connect to their middle and inner ear. So the ear wax plug doesn't really mess with their hearing at all. It's like completely 

laura: evolutionary leftover from when they were on land. probably. 

katy: Yeah. One of the brave souls that studies these, which this is also very interesting. His name is Dr. Steven Trumble from Baylor University.

All right. Just down. I have 35 from me. But it's a very, it's Texas yes, we have a coastline, but from Baylor to the, it's a very landlocked university. Well, him and one of his colleagues, Dr. Sasha Esco, They figured out how to read whale ear wax, basically like a biography. But in the earplug, in one famous case, they examined a blue whale's earplug that was over 10 inches long.

And inside it, they found 24 distinct layers. So, I mean, you figure every six months, it was actually fairly, fairly young. [00:07:00] Each layer, like we said, captured six month period of the whale's life. And their work showed that whales aren't just like big and, okay, lemme back up here real quick. So the purpose, 'cause that's one thing people don't understand, like whale's purpose and that yes, there's food chain, everything like that, but they very much so what they call quote unquote whale pump.

So whales, oftentimes they eat deep in the ocean and then they surface. And that's where they go to the bathroom. And so then they lay their xmen up there, which helped. And so it's a, it's a cycle, you know? So that's kind of like a whales, a whales purpose. But if we think of them now as studying these earplugs, now they serve a whole other purpose because they're straight up like the ocean historians.

So every time humans dump pollution into the ocean, it ends up stored molecule by molecule in those wax 

laura: Yeah, because usually 

katy: when Tru 

laura: is really like, attracted to [00:08:00] lipids. Like fats in particular are like really absorbent for

that kind of stuff. 

katy: Yep. So when Trumbo and UNESCO compared modern plugs to those collected decades ago, they could actually see how even stress hormones in other contaminants have increased alongside industrialization and wailing. So it like when we knew we hit yeah, peak, like wailing and stuff like that, and industrialization, what they found in those layers completely changed.

And so you can not only reconstruct a whale's lifetime, but also think of your Garmin watch, like profile of stress. All right? That's kinda what we could do with these, with these whales is monitor what they've gone through in their entire life. So somewhere in the lab there's these scientists, like these two down in Baylor that are carefully slicing through, which is so gross, what looks like a ba, basically a giant beige looking candle.

And just [00:09:00] figuring out the whale history. So it is pretty gross. But why, I guess the big question then is why does any of this matter? So I kind of hinted about it, but that giant wax baguette isn't just biology. It really does give us a more accurate picture of climate history, pollution data, stress, diary.

'cause we look at all like the stress and everything that whales are facing with sonar and everything. And so when Dr. Trumble and Dr. Esco started analyzing these plugs, they started literally finding traces of things like DDT, heavy metals and even shifts in the cortisol to that's tracking all the stress.

And so they were able to compare. And again, I mean the only. Because it doesn't fall out of their ears. Obviously the only way you're gonna get these is once the animal passes 

laura: Yeah, 

katy: So whenever they have been able to find, and it's like we've known that, well everybody but me apparently has known that these [00:10:00] things have existed for a long time.

Yeah. I had no clue. And so whenever they would take and look at the old samples, now again, this is a mini sew guys, but did I spend way too much time going down rabbit holes on this one? But when they started collecting like the older and looking at the older example, 'cause museums would have these, but they didn't really look into it until these two really kind of pioneered it.

And so when they started looking at the older ones, we truly have an accurate picture of an ocean time machine, which, and we don't really have that necessarily in other things. Like where it's like the 

laura: it's like an ice core, like what they look at in the

Arctic, but it's for the 

katy: exactly. Ex. Yes. Exactly. Exactly. So it's an, it is important to study these things so then we can see the impact because, , whales are important to have in the ocean.

And so if we see these species that are declining, we can study those earplugs to be like, okay, what happened? Why do we have an estimate on where? And so now that we're tracking also all these [00:11:00] animals and they're, studying the migration patterns and things like that, they can combine that to, to really tell like in a more accurate picture of not just whales, which are easy to track.

Now 

laura: and long lived, like this is a, a long term study. 

katy: it's a long, very long-term study. We can start to combine those and really paint an accurate picture because again, when things like the coral reefs and everything start dying in the ocean, that's nothing but bad news coming for humans on the land later on, 'cause it's.

S ocean temperatures rising and all that stuff. So being able to study these things really is a good indicator of that. I don't know,

laura: Like Ocean 

katy: Canary in a coal mine situation. Yeah, yeah. To be able to see what, what's going on. So yeah. Whale, ear, earwax, archivist. I had, again, I have no idea. When I read that, I was like, wait a minute, what?

And again, it was like one, again, one of those things where I felt 

like 

I [00:12:00] would, how did I miss it? I don't know how I missed it, but I'm so glad I found it now.

laura: telling that's your career to either your new in-laws, your high school reunion, whatever it is. That's an amazing title. My guy, my

last guy with the swearing, he, he could probably say something like, I mean, he is a psychologist at the end of the 

katy: Linguist. 

laura: Yeah, yeah, yeah. But not 

katy: But whale ear wax archivist. Yeah, which is so specific. So, and they have the, they have of course 'cause now Baylor University, the lab under Dr. Trumble and stuff like that, he's kind of like the lead on all this stuff. And so he has more and more students that are studying it.

And again, the stuff that they're finding and the papers look up some of their work. It's really quite interesting and fascinating as it is sad. But again, it's gives a accurate picture of, hey, we can change this since we know what this kind of stuff is leading us towards. So, so, yeah. 

Very cool.

All right guys, go make sure you check us out on [00:13:00] Patreon and support us there. If you can look us up on our social media Wildly Curious podcast and we will talk to you guys next week with another long episode.

laura: ya.