Dr. Rebecca Lewison
Appearances
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So it's convergent evolution? Yeah. And a lot of the structures that they have are not that similar. But one of the things that I know people sometimes get fascinated about common hippos is that they are most closely related to whales and cetaceans. No. No.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Yes. And we know this from all lines of evidence. It used to just be morphology, morphological evidence, and they did looking at fossils and different parts of the animals. But as Science progressed and we started using genetic information. They've used all sorts of genetic tests to demonstrate that they are in fact sister taxa, cetaceans and hippos. No.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Why are their mouths so big? That's a good question, actually. So pygmy hippos don't have the gait like common hippos do, right? Common hippos have like 180. They can actually open their jaws that much.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And it is a good question why, because it's not like they're eating pumpkins and big things in the wild. I will say that male hippos, sometimes you'll see male hippos engaged in what looks like, we're going to say like this mortal combat. I don't think it usually results in mortality, but they do use their gape
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
both, I think, against other hippos, you know, if they're having a territorial fight, and other animals. They're pretty badass. How big are their teeth? Well, so they have different types of teeth. They have sort of molars, and then they have canines, which come up, which can be 9 or 10 inches. And then they also have incisors. The canines are actually most similar to elephant tusks.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
What are they used for? Again, it's probably just some type of defense.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And it's a bummer for them because those canine teeth actually do have ivory. Oh. So it's not as high quality as elephants, but it's one of the reasons that hippos have gotten wrapped up in the ivory trade. or legal ivory trade is because they're canines. So those are the ones that are sort of the curved ones coming out of their bottom jaw have Ivory, made of ivory, yeah.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
All right. You ready? They aren't even swimming. No. They can't swim. They sort of glide, walk, run along the bottom. So they're never in deep water? They can be in deep water. They can be submerged. They can stay under for about five to six minutes, but they're not actually swimming. I guess if you think about like if you were doing aqua aerobics.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
I was just going to say, this is like going to the Y. What? Yeah. Don't try this with them, but it is just like that.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Yeah, that's a really good question. What are they doing under there? So one thing, remember we talked about them being related to whales. They have nostrils on the top of their... So if you look at a hippo, let's see, how do I describe this?
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And they actually have muscular and anatomical features that are similar to blowholes. So the nostrils close when they go underwater. And when they come up, one of the ways you know that there's a hippo there is because you hear the right, when they blow out. And so that's similar to what we see with cetaceans, right, when they come up and they're blowholes.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So there's actually some characteristics of their nostrils that are similar to that. What do they do underwater? It's hard to know because we really, it's very hard to see. Jacques Cousteau famously like put this fake hippo and people have tried this, like deploy like a autonomous, you know, vehicle in the water dressed up as a hippo.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
It doesn't go very well for the daughter of the vehicle, right? The hippos are just like, no, get that thing out of here. So it's pretty hard to see what they're doing. And mostly they're in water that is not clear. You can't see anything.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
I do want to say as I, because I think I have to represent for the hippos on this one, that more hippos die as a result of hippo human conflict than humans, which is not to underestimate the devastation that happens when there's a fatality, but I don't think hippos are naturally aggressive to people. The biggest threat that they face is habitat loss. They rely on fresh water.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
We rely on fresh water. We want to put a farm next to a river because that's where it's easy to grow crops. That's where they live. They're obligate in the water. They have to be there. So it's not like they can just pick up and move. There has been an increase in hippo human fatalities recently. And I think it's really just an indication of habitat loss.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Yeah, it definitely happens with people fishing in boats. It happens with tourists in boats. It does sometimes happen on land because hippos are crop raiders. Turns out they love eating. We just said they love pumpkins. If you plant some, they'll come eat them. It's not usually pumpkins, but like corn or beans. They do a lot of crop breeding to their defense.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
You put the food right next to where they live.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Yeah. And much higher quality nutritionally than anything else that they're eating. So it makes sense to them. But it's a definite problem and it's really tough to develop deterrents. you know, people talk about electric fences, but a lot of this is happening in places where there might not be electricity or a lot of infrastructure.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And so it's a real challenge to figure out how to get hippos and humans to coexist.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Common hippos are in 38 countries. And so it's a challenge to to get all that information. But our best guess is probably something around 130,000, which is not a lot. In the world? Yeah. I mean, well, recently we only count the ones in Africa.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Yeah, in Africa. And that's about probably a third of the amount of elephants that we have. And so it's a real issue. And the problem is when I would tell people, oh, I study hippos. First of all, that's crazy. And we're concerned because their numbers are declining.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
If you're in a place where there are a lot of hippos, someone's going to turn around behind you and be like, excuse me, do you see that large group of like 50 to 100 hippos? But they aggregate. And so it may seem like there's a lot of them, but there's been a tremendous amount of loss of habitat. And, you know, 130,000 is not very many.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Yeah. I think most people know, like I said, sort of East African countries, Kenya, Tanzania, Uganda, Zambia, South Africa, Botswana has a lot of hippos. The place that we know hippos are probably most vulnerable right now is West African countries because there's much more population growth, less habitat for hippos, a lot more pressure on freshwater resources.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And so I think there's probably people in countries like Nigeria or Guinea or Guinea-Bissau that they may not even know that they have common hippos because they exist in such low densities.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And there's some disagreement of whether there are or aren't subspecies. But there are potentially as many for subspecies.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
There aren't very many of us. And part of it is because hippos are really hard to study. They're these animals that are hiding in plain sight. They're in the water during the day. It's very difficult to tell them apart, right? With elephants, we have big ears that you can identify individuals and you just can't. And they're just not on a lot of radars for conservation organizations.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So they haven't gotten a lot of funding. The hippo community is thin on the ground. Oh. Well, you mentioned big ears.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
That is a good question. We don't really know, but it could have to do with the fact that most animals that develop in the water, like sea lions, have pretty tiny ears, right? And so I think we don't tend to see animals that have, you know, come up evolutionarily in the water with big ears.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
I don't remember engaging too many people, but I certainly told my whole family and the people I was with, this is not accurate. There's a lot of that. The one thing people ask me when they find out that I work on hippos is kind of where we started. Do they really kill more people than any African animal? I don't know who started that, but it certainly wasn't me. And I don't think it's accurate.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
It is not fact-based. I think snakes kill way more people than hippos. I think the reason it started sort of this urban legend is because it's surprising. It's surprising that for people to know how fast they move on land. And the answer is faster than us. You know, maybe 19, 20 miles an hour they can run. They can move extremely fast in the water.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And I think that there has been an increase in hippo-human conflict. And that takes people by surprise because they're not particularly aggressive, I think, naturally. I think what we're really seeing is habitat loss. They're under tremendous pressure. And so the number of attacks is on the rise. But I just want to tell people now, I don't think hippos kill humans.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
more people than any other African animal.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Yes, exactly. That's who started this whole thing. It was the mosquito lobby trying to point the finger at hippos.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
I don't think that's true, Debra. Okay. I think bubbles and wiggling is not the thing you have to worry about. I think the real thing you have to worry about, people ask me like, what do I do to sort of like fend off an attack? And you know, the answer is like, wait, why are you in a place where hippos can attack you? The thing we need to do is avoid them and not be in those spaces.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Now, if you're a commercial fisherman in an area that has hippos, you know, it's a different situation, but most of us aren't.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
I started studying hippos as a graduate student. I was at UC Davis doing my PhD in ecology, and I kind of stumbled into this project to work on hippos. My interest in was to study behavioral ecology. At the time, I just really loved, it was fascinated by sort of the minutia of animal behavior. And I thought, oh, this will be perfect.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
No, they are not monogamous. They don't mate for life. And in fact, they don't really form bonds like that. So hippos are something called polygynous, which means there's a single male, the dominant male, and lots of females that he probably mates with. Hello, ladies. And that herd is like that, sort of with one male and lots of females until...
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
another dominant male comes over and challenges that hippo for that territory so when you see the you know national geographic pictures of two hippos with big gapes sort of going at it with those big teeth we were talking about like what those are for those are territory fights for control over one of those polygynous herds got it they're kind of like in a bar fight
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And the answer is we know almost nothing about hippo communication. Why not? They're communicating in the air like we are, but they're also communicating in the water. And we don't really understand how they're doing it. We can record them. And people have done that. And they describe sort of clicks and other types of noises underwater.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Like that, right? It's not a great one. I'm probably not going to call them in. But I think it's these crazy noises. And we really don't know anything about what it means, what they're saying, how they're even communicating in the water.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
I think it's interesting because honestly, it just feels like one of the wonderful mysteries of hippos, but it's also one of the things that's kept them, I think, off the radar and kept them sort of in this area of we see you, but we don't know anything about you. It's just that they're so tough to study.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Yeah, it's a really crazy, crazy thing. So if you're just new to this, Pablo Escobar, who is a very famous narco trafficker, had four hippos, three females and one male on his ranch and compound. And upon his death in 1993, for some reason, they just left them.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Cut to this many years later. And now there's probably around 200 hippos roaming wild in this area of Columbia called the Magdalena River. Turns out it's a great place to be a hippo. Oh, no. So hippos do really well under good conditions. It's one of the reasons why hippos can start having babies like four years earlier in captivity. It's because the conditions are so good.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So that's what we think happened in Colombia. There's grass everywhere. It's never a dry season. They never lose water availability. There's unlimited food, unlimited resources, and that's why we've seen this population explode. So what do we do now that there are 200 and maybe more hippos in Colombia? It's a really tough problem.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
I'll study hippos, which anyone who actually studies behavior will be laughing when they hear this because you think like, no, no, no, no. You study behavior on small things like birds or squirrels, not hippos.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
There have been some suggestions and solutions that they've tried, but all of them take a lot of money. They've tried darting some with contraception. They've tried castrating some of the males. They have actually culled one individual, so they've shot him. And that may sound terrible to some people, and I'm obviously not
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
concerned about hippo welfare, but I'm also concerned about the welfare of Colombians who live there. And there's lots of rare and endangered species in Colombia. There's no easy solution here. From my perspective, my focus is on protecting hippos in Africa. And that's where we need to be focusing our resources.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So the idea of people have talked about like trying to send them to captive facilities, but It doesn't feel like a great use of resources to me because that's not really where they're supposed to be at all. The only reason they're there is because someone had hippos as pets.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
They do. And I never have. I'm a vegetarian, but people do eat hippos. There are some groups of folks who have taboos in certain countries, in certain areas against eating hippos. But in most of the places where I've been, people do eat them. They have very thick fat layers and sort of like pigs. And I've heard that they are extremely yummy and, you know, people eat a lot of the parts.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And so that's a lot of meat for a lot of people.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
But I had this opportunity because I had spent time in Kenya as an undergrad and so could speak some Swahili and had traveled around and just had a fair amount of field experience. And so I got this amazing opportunity and kind of just fell into it and didn't realize what I was getting into at the time and sort of entering this amazing world of this understudied animal.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And one of the threats to hippos is unregulated hunting. And in large part, it's because they just sit in the water. You can take them out with a muzzleloader, you know, an old gun. They're just sitting right there. And then you have 2000 pounds of meat. So in some places where there's been civil unrest or really hungry people, which makes a lot of sense, right?
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Hippo populations have declined dramatically because people have needed to eat them to survive.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
In general, I think the only predator they really are concerned about is people. They're not worried about crocs. That's when crocodiles, that's the question that comes up. People ask, oh, you know, crocodiles eat baby hippos. Crocodiles do not stand a chance in the water. Oh, really? Mom hippos are extremely protective.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
as moms are in lots of places, that there's no chance that the crocodile's going to get them. I have seen lions taking down juvenile hippos, so I know that it happens, but I don't think it's particularly common.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
The one best friend I can think of is a really cool mutualistic relationships between hippos and oxpeckers. So if you see hippos that are out of the water or just partially submerged, you'll often see a particular type of bird that sits on them. It's called an oxpecker that actually eats like ticks and other insects. So the bird gets free lunch and the hippo gets cleaned.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So that's definitely a friend. In terms of their social structure, I think they are really social animals themselves. We don't understand like who's related to who in those herds. Again, we can't barely tell them apart. And for most people, unless you spend a lot of time looking at hippos, you can't even tell males and females apart unless they open their mouths.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Their canine teeth for the males are much thicker. Their head structure is different, but like they're not sexually dimorphic, right? Sometimes males and females are really different sizes or different colors. They're all gray. They're all fat. They're all really big and you really can't tell males and females apart when they're mostly submerged.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Sometimes you'll see like creches, which is like groups of females and lots of offspring, like lots of calves, and they can play together in the water. But again, that's because there's these big groups where it's one dominant male and lots of females and their offspring.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
That is definitely true. There is so much of it. And we actually think that hippo poop, and not just the poop itself, but all of the compounds like silica and silicon that's in there, are really important nutrients for the water areas, the wetlands, the rivers, the lakes where they live. And there's some evidence that when hippo populations decline, fish populations also decline.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
It is true that hippos, when we ask, like, where does a hippo poop? The answer is anywhere it wants. Mostly it is in the water. But with males, we do see that marking behavior. Another crazy thing. Ready for this?
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
You can't study it in the lab. You can't manipulate it at all. They're actually really hard to study, period, because they spend almost all their time in the water. You couldn't pick something less studyable if you tried.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So what males do is they come out of the water, they start peeing, and then they spray it backwards. And then with their tail, use that to spread with the stream of the pee and the poop coming out. It's gross, and yet extremely effective. And I think it's territory marking, although we don't really know this, because we really only see males do that.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So we think they're marking their territory, you'll see it as they come out of the water, they kind of do this at a couple places, sometimes they'll smush it against like a tree, or, you know, a rock. And I and we think, again, we don't know this for sure. But we think it's dominant males marking their territory.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
There's just spreading the love, right? They're spreading what they do best. And it is one of the things they do best. They're really important nutrient movers and ecosystem engineers in that way.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
No, mostly when they're sleeping, they're resting above the water. So I remember I was thinking like, imagine there's sort of a log, that's the hippo's head. And so mostly when you see them resting, it's they're resting on the bottom. And that's one of the reasons why their nostrils are really at the end of the log, that's their head, is so they can breathe that way.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So they're only underwater, again, at like five to six minutes, maybe max at a time, it could easily be less. They're not sleeping underwater.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
They look like logs, honestly, when you go to an area where there's a lot of hippos. And so there's sort of this like small top of the log, that's the hippo that you can see. That's them just sort of And actually I should say, are they sleeping? I don't know. They're certainly resting.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
We don't 100% know what they're doing when they're in there in large part because it's not safe for us to get in there and find out.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Absolutely. It's an amazing technology that I think has changed a lot. One of the reasons that it's so hard to find out how many hippos we have, that seems like such a simple thing, just go count them like elephants. The problem is when you go do a flyover, right, you take pictures, that's one of the ways that we count, you know, animals in remote areas.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
At any one time, there could be 30 to 40 percent of the populations that submerged. Right. They heard a noise and they got scared. And so now they're under the water. So you can't see them. And so drone technology has been amazing opportunity to be able to really count hippos and just get some basic questions like how many are there? Where are they? How are these numbers changing?
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Who didn't play Hungry, Hungry Hippo as a kid?
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And I know it sounds really basic, but. for something that's the fifth largest land animal, we still don't have great data on that.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
It is not a familiar term with me, but it does kind of make sense. There is certainly a dominant male. And again, people always say like, well, where are the rest of the guys? The rest of the guys live in a bachelor herd at some distance away from the rest of the herd. So it's literally all the other males. So
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
at some point juveniles get kicked out of the main pod and they have to go with the bachelors. And that's where all the other adult males go that aren't the dominant male. So you can find a bachelor herd that's associated with a large polygynous herd.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
That's exactly it. That they're waiting for their roses. They're waiting for their turn at bat. And they, might challenge that male, right? And that's when you'll see those cool sort of like big gaping fights where they stand off and, you know, fight on the beach. So maybe that's the beach master.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
What are they eating? Are they eating mostly plants? They are eating mostly plants. So they are herbivores. They eat grass. So we can be a little bit more specific than that. They're basically like lawnmowers. They eat a tremendous amount of grass and it has to be pretty short grass. Why? Well, because it's just wait till we unpack this.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
It's very challenging to know how much sneaking there is, right? For a lot of species where there's like a dominant male or even monogamous couples, there's still extra pair copulations, we call it. And I don't know how much sneaking there is. So it's possible that those bachelor males sneak and get access to the females, but we don't know.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And that's something that if we could get like tissue samples or be able to do genetic testing to be able to kind of figure out lineages or which calves are related to which parents. It's so hard to get to them. And it's almost impossible to tell them apart. Hippos just don't have any structures. It's rude probably to say they all look alike, but to our eye, they really do.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
I have touched hippos in captivity. I have touched dead hippos. I have not touched a live hippo in the wild. I've never been that close or in, you know, I wouldn't do that, but it's a great question. Like, how do we get samples? Another question is like, why don't you just put a collar on them? What's the big deal? Go figure out where they go on the collar front.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Turns out hippos don't have a neck. Most of the collars go around the neck. They don't have a neck. What they have is a head that's attached to the rest of their barrel-shaped body. You can't put a collar on them. So most of the technology that we have for tracking rhinos or tracking elephants won't work on hippos.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
In fact, a colleague of mine, the first tag that we put, and it wasn't a collar tag. It was like a tag that they attached... just on the skin, wasn't until 2013. And it stayed on for like a kilometer. Amazing feat, but really, really hard. So hard to figure out where they're going. And to get samples from them.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
The other thing about hippos, remember we talked about they're amazing from head to tail. They have one of the thickest hides or skins of any animal. hands down. In fact, people used to use hippo skin to make whips because they are the most durable and hardest. So actually even getting a dart or something like that into a hippo, very, very hard.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Like hippos are amazing head to tail, but they don't really have a neck. They don't really have any structures in the back of that part of their spine. So they can't really lift their heads up like when you think of like giraffes or elephants. They can't do that. So they're really limited by the grass height.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
They don't sweat blood, but it is sort of a reddish orange pigment. And that is something that people have isolated because they were able to get it off a captive hippo. And a fantastic group of scientists from Japan in 2004 was able to extract some and figure out like, molecularly, chemically, what's going on here. And it's just, as you said, it's not blood.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
It is a secretion, but it is a sunscreen and probably an antibiotic. Oh. And we think that that secretion both protects them from the sun, which we know is very important. We talked about hippos, the need for water and important for their thermal regulation, but also that secretion seems to be an important antibiotic.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
I wish I had it, right? I could really use that sunscreen.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
You know, I've asked for a couple other places. Like she does seem to have a very lively personality. Nothing that she's done that I've seen, it seems like out of the ordinary. Anybody who's taken care of kids, like they open their mouth all the time. They're pretty demanding and they want attention. And she seems to be extremely healthy and just, you know, a lively pygmy hippo.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
One thing that's been wonderful about having Mudang on the scene is that people know about pygmy hippos. And a lot of people maybe didn't even know they existed. They're not just smaller common hippos. This is a separate species. It's endangered. And, you know, I think This will be the only opportunity for most people to ever see a pygmy hippo.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
In fact, even people who study pygmy hippos, again, we only got pictures of them in the wild in 2006 from remote cameras, not a person with a camera, a camera out there by itself. There's so much we don't know. And I think that having more people aware of pygmy hippos is great. The thing that really upset me about the story is knowing that people threw things in the enclosure.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
You know, there were people throwing shrimp or other types of food. And hopefully everybody who heard that story realized that's the thing that's a danger. Like you can never throw anything into an enclosure that has a wild animal. You may think you're doing you know, something good, but they have a very strict diet.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And I think having folks being respectful, you know, being quiet is a great thing when you go see animals in captivity because it is stressful and it is important that we're mindful of what their experience is like. So I appreciate those concerns.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Yes, that's a great question. And it's a little bit of a yes. They do forage on the banks. But what you'll see if you're in a place where there are a lot of hippos is you really know a lot about where hippos are going because they have these trails. And you can look down on the trail and see like a hippo print, another hippo print. So they just follow these trails for a really long time.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Thanks. This is a really important point to talk about, which is We talked about hippos being threatened from habitat loss, which is just us encroaching, developing areas around freshwater. But climate change is another real serious threat, particularly for common hippos, but probably pygmies as well. But they rely on water resources.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And a lot of the places, a lot of the projections of where we think what's going to happen, it means less rainfall, less standing water. I think it's a real threat. it's getting closer as we think about like ensuring coexistence of people and hippos into the future is the fact that the climate is changing and they are so sensitive to these climatic shifts.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So I would say when we think about like winners and losers of climate change, I would put hippos in the loser category, you know, and it's something that we absolutely, it has to be on our radar because these are the resources that they need.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Yes. The whole they kill more than anyone else. If I can do one thing in my lifetime, I feel like it's dispel that. Why? No, it's not right. It's not accurate. Stop saying it. The other flim flam, I guess, it's really just this idea of like, oh, there's so many of them. It's not true.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Like I know that they are abundant and they come in these big groups, but they're really declining in a lot of places. And even in areas where their populations may be stable, they're losing habitat, either directly from human development or because of climate change on slightly longer scales. But I think that's a really important one. And I care about elephants too.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Like I sometimes come across as like grumpy about elephants. But if I am, it's because elephants just get so much attention. And I know they have incredible behaviors and they, you know, mourn their dead and they communicate where we can't hear them and amazing things. But I think hippos have all of these things too. It's just that we can't see it and we don't know it.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
But they're these incredible animals, certainly worthy of a future.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
I think the worst thing is just that expectation of, oh, well, we know everything, but we don't even know how many there are. Like basic, basic things. And that's sometimes frustrating because, you know, you kind of have to start the conversation from the scratch. And so studying hippos is about studying human coexistence with them.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And I'm really hoping that the next generation of scientists can use that technology to really think about innovative ways of to protect people and protect hippos and their habitat.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So they're really well established to what we call grazing lawns. So areas of short grass that are some distance away from usually the water where they're in.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
I honestly am captivated by them sort of as these like organisms. Like I said, I am fascinated by all those adaptations, all these things about their body, whether it's their teeth or their stomach or their skin. It's amazing. And it feels like every time you sort of look under another part of the hippo hood, they have another incredible adaptation to being these
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
semi-aquatic sort of like half whale, half antelope, you know, and that's incredible to me. And I still find myself captivated. I mean, even though I've been studying this for a long time by those adaptations, by all of the things that their bodies are able to do and navigate.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
I would. I know better. We don't touch wild animals in the wild, but they're incredible. So yes, I can safely say that if I happen to find one next to me that just wandered up and I could touch it safely... I absolutely would.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
They probably don't give a hoot about any of that, but I would love that if that could really translate to people's passion of saying, I want to live in a world that has hippos, that has pygmy hippos, common hippos, and I want to know that they're going to be here for a really, really long time.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
It's not them. Yeah, absolutely.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Yeah, it's crazy. We think they eat somewhere between like maybe 50 to 100 pounds. We don't 100% know because it's hard to tell. And obviously in captivity, their diet is much better. You'll see them like eating watermelon or pumpkins, you know, if you've seen the videos. So they're not necessarily super particular on the species of grass, just the height of the grass.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So I think these grazing lawns are there because of them. And they continue to get mowed down by hippos. And they're pretty long lived. So I'm sure they have a lot of information that they store. And if you want to study, like if you were a graduate student and you were captivated by foraging behavior, that's what you do. You'd follow the paths. You'd sit in a vehicle and you'd get some...
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
crude night scope and you'd watch them for hours and hours and hours. And that's basically what I did. Are they nocturnal? Yes. They only come out of the water at night. What? And we think that's because of thermoregulation, right? They're adapted to be in the water. They don't do well if there isn't standing water and they'll die without that. So in the dry season.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And so for most of the year, they are only coming out of the water at you know, when it's dusk and getting dark. So yeah, what I would do is sit, I would drive my Land Rover to the place where that foraging lawn was and then I would sit on the roof with a pretty old school night scope and watch them forage. That was, that's what I did for about a year.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
I have some crazy stories of falling asleep and like waking up to elephants at my eye level because I would fall asleep. Like you said, I wasn't getting enough sleep. But yes, I would sleep during the day and try to stay up. And I would have to do it when there was some full moon because it was really crude. It was, you know, mid 90s. So we had night scopes, but nothing like we do now.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
The incredible thing is what I remember doing is picking my head up and I'm literally at eye level because I was on the top of this pickup truck and I literally just picked my head up. I saw an elephant and I was so tired. I just put my head down and went back to sleep. No. Yeah.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
I think I woke up in the morning and I definitely was like, What? But, you know, for people who work in the field and yeah, obviously I was careful and, you know, followed all the protocols I was supposed to follow, but amazing things happen.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So I'm going to say it out loud and then people are going to think like, what scientists do, what? But I was actually counting the number of bites and steps. I know, I say it out loud and I just think, what? And it does sound like minutiae to me too, but it's fascinating. Like we know what we do. What do hippos do? How far do they go? Can they just go anywhere?
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Like you were asking those questions initially. So I spent all this time trying to understand sort of their strategy. How do they make it work? How do they get enough? How do they decide where to go? And how do you make choices about where to forage?
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
They don't. Hippos in captivity, all the accredited places that hippos are living, takes amazing care of the animals. They give them lettuce and pumpkins and watermelon and amazing things and very, very well fed. But no, nothing like that happens to hippos in the wild.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Yeah, we think they live around 30 to 40 years in the wild. And in captivity, they can live quite a bit longer.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Okay, so memory said they are incredible head to toe. So they have incredible stomachs. So anyone who's like fascinated by stomachs, there's not going to be a very large slice of listeners, but
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
They have all this interesting stomach structures that actually is similar to what cows have. They are not ruminants, but they do have this like blind sack. They have like this three chambered stomach, but they do something similar to ruminants. So they don't have like cud, but they keep things in their stomach a really long time.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And I think that gets to your question, like way more than elephants are like conveyor belts. It goes in and it goes out. And if you see an elephant poop, I don't know who has, but you'll notice like, oh, I know what that is. It looks just like what they just took in. But for hippos, not so. So it really breaks down a lot so that this three-chambered stomach has this ability to extract resources.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So even though 50 to 100 pounds sounds a lot for wild hippos, like you said, they're size of a VW bus. And so they're using this three-chambered stomach structure to extract all the nutrients and keep things in their stomach kind of a long time.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So they're about like 2,500 to 3,000 pounds. In the wild.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
Really, really quite a bit smaller. Yeah.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
This is the reason most people don't. It's because pygmy hippos are only in West African countries. And even within West African countries, they're only in four of them. And they're very, very secretive.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So we think of common hippos right there, this iconic animal of the African savanna, right? You'll see a picture of like a big hippo gaping with a sunset behind it. Until 2006, we hadn't even ever had a picture of pygmy hippos in the wild.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
And it's because they're very rare, right? They're an endangered animal. And there used to be a very large forest complex there. in Sierra Leone and Liberia and Guinea and Cote d'Ivoire that kind of went over that entire region. It's largely been lost or there's been a lot of habitat loss of that forest. And that's what pygmy hippos rely on. They're also solitary.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
So they don't do this big group aggregation that we see with common hippos. So it's not surprising. They're secretive and solitary cryptic forest animals. And there's very, very few of them.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
San Diego Zoo, you know, fantastic zoo. When I used to go with my kids and we'd be standing at the pygmy hippo, people would say, oh, these are just baby hippos.
Ologies with Alie Ward
Hippopotomology (HIPPOS) with Rebecca Lewison
What did you say? I corrected everybody, whether they wanted it or not. But they do look, honestly, to me, they look very different. But I can understand why people maybe think they're the same thing, only smaller. So for everyone listening, they're absolutely not. Pygmy hippos are a separate species. And actually, evolutionarily, they split. from common hippos like millions of years ago.