The downside of giraffes' long necksPlay
On a sunny day in March 2020, researchers in South Africa discovered the bodies of two giraffes. From what they could tell, the giraffes had died a few days earlier. But the cause was a mystery.
One of the animals had a broken right ossicone, one of the horn-like bones that crown giraffes' heads. The other appeared untouched. Both gave off the odd smell of ammonia.
To understand what happened, producer Dean Russell turned to the subreddit AskScience. He discusses his findings with Endless Thread co-hosts Amory Sivertson and Ben Brock Johnson.
- AskScience: Got Questions? Get Answers. (Reddit)
- Giraffe Conservation Foundation
- "The Last Giraffes on Earth" (The Atlantic)
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This content was originally created for audio. The transcript has been edited from our original script for clarity. Heads up that some elements (i.e. music, sound effects, tone) are harder to translate to text.
Dean: Amory. Ben.
Dean: I'm going to start with something I read online recently. This is a mini murder mystery.
Amory: Oh, boy.
Ben: Does that mean the person, place, or thing that was murdered is miniature?
Dean: Well, actually, the opposite.
It's March 2nd, 2020, and a team of researchers are trekking through this wildlife preserve in South Africa. And they come across these two female giraffes lying on their sides. And it doesn't take long to discover that these two have unfortunately gone on to greener pastures. But there's something really strange about their deaths. The cause was an absolute head-scratcher because these two giraffes looked — besides the fact that they were dead — more or less fine. Like nothing was wrong with them.
Ben: Hmm. Broken neck.
Amory: A broken neck, they would be able to tell. So I'm going to say that this is some little bug or parasite.
Ben: Like driving under an overpass in a Volkswagen bug convertible?
Ben: Is that not what you're thinking, Amory? You're not? Not that one. OK.
Amory: No, I'm thinking of little critters that would be, you know, many, many, many feet below where their head is, to notice them latching on to or biting or embedding themselves within that giraffe body.
Ben: What about headbanging? Could that be a thing? Like they were listening to rock music too loud, and they head-banged too hard, but their necks are so skinny that they just—. No?
Dean: That was the number one thing that they considered. Yeah, for sure.
Dean: So, I will say, in this bushland preserve, which is called Rockwood, giraffes — which are an animal that's considered vulnerable to extinction — they are highly monitored. And the last time that these two had been seen with their herd was a few days earlier in a storm. Now, that storm itself was pretty brief, but it had done some damage to several game fences. And so naturally, you might think someone or something dangerous had got in. They kind of failed to see any gunshot wounds, though. There were no, like, lion claw marks. There were a few jackal bites, but jackals are scavengers. And, you know, they don't really attack giraffes. And then they notice this weird toxic smell, like ammonia, which was emanating from their bodies.
Amory: Oh, no. Did they eat something that was toxic?
Ben: Something that's, like, hard to swallow because, you know, with the long throat, it just might take too long?
Dean: Oh, these poor giraffes.
Ben: I love giraffes. Don't get—. Please don't, you know, don't get me wrong. I just—.
Amory: You're just fully appreciating their anatomy.
Ben: Yeah, that's right.
Dean: The older giraffe — I will call her Gina. She was found lying on her left side. She had a broken right ossicone, which is that horn-like bone on their skull.
Ben: Hmm. Damn, Gina.
Dean: Yeah. And so they think maybe Gina fell. And her buddy, who I'll call Gabby, Gabby is lying 20 feet away, completely untouched. And it appears that they died at the same time, as if they both just, like, shorted out.
Ben: Wow. This is a real Thelma and Louise situation here.
Amory: No, we know how they died. They got back in that Volkswagen you were talking about.
Ben: Yeah. But, you know, maybe this is like the people who happened upon Thelma and Louise, and they're like, What? There's this car in there. What?
Dean: So the reason I bring this up is because, as I was reading this — I was reading this in this academic journal article by Ciska Scheijen, which I am sure I mispronounced, and so please forgive me, Ciska. But one of the researchers, she wrote this up, and I was reminded of this old post on the subreddit — the subject of today's show — AskScience.
I'm doing a lot of talking. Does someone want to explain the deal with AskScience?
Ben: It's a community based around science questions in which people who might have some level of expertise respond to said questions with surprisingly effective answers. Most of the time.
Dean: This is, in my honest opinion, my favorite subreddit. I love going through AskScience. I love seeing the ideas that people come up with, and I love seeing how they, like, solve things together. But so several years ago, someone posted a simple question that felt very relevant as I was reading this murder mystery because Gabby and Gina, as I said, they died in a storm. And this one post asks the question, "Do giraffes get struck by lightning more often than other animals?"
Amory: That's, that is shocking. But it also, I guess, makes sense because if—
Ben: It is shocking. Couldn't be more shocking, shocking to the point of death.
Ben: Does it make the hairs on the back of your neck go up, by any chance?
Amory: Well, I was going to say because I'm like, they're still not tall enough to be struck by lightning. But if you think about their natural habitat, they might be the tallest thing in the area when lightning strikes. So Gina and Gabby got struck by a bolt of lightning at the same time?
Dean: Well, before I get back to the mini murder mystery, I wanted to pull apart this more general question — Do giraffes get struck more often? — and see if it actually tells us anything about what happened to Gina and Gabby. And we'll do that after the break.
Dean: Ben, Amory, do either of you have any guesses before we dive in: Do giraffes get struck by lightning more often than other animals?
Ben: My current feeling, Dean, is that yes.
Amory: Oh, that was a pun. I was like—. I thought that was—.
Ben: Oh, my God. This is a hopeless endeavor.
Amory: I thought that you were hinting. I'm sorry. I thought that you were hinting at the fact that maybe you knew even more, and so you were trying to play along with this theory for the current moment, but you were making a pun. My current feeling is also yes, but that it's so incredibly rare that the idea of posing this question is kind of silly, but maybe not.
Ben: Maybe Dean has something that can ground us.
Dean: You know what? I called someone to help ground me because the giraffe science was—
Ben: Was it above your head? Was it over your head?
Dean: Oh, my God.
Michael Brown, Ph.D.: You know, I love this question because it really plays off of people's fascination and curiosity with giraffe.
Dean: So this is Michael Brown. He's an ecologist at the Giraffe Conservation Foundation in Namibia. And he thinks, you know, this is a really interesting question. The giraffes he studies are like 15, 16, sometimes 20 feet tall. And it is true that sometimes lightning — often actually — strikes the tallest object.
Michael: But to say that they're more susceptible and more at risk than other animals? It's really tricky to say.
Dean: You know, even though I could tell you that like 20 to 30 people are struck by lightning in the U.S. every year, there are no data on giraffes.
Michael: Giraffe live oftentimes in remote places. So collecting any data systematically on lightning strikes is an inherently challenging thing to do. So all the accounts you have of animals getting struck by lightning are, you know, purely anecdotal.
Amory: Unrelated side note: Is the plural of giraffe "giraffe"?
Dean: (Laughs.) That was my second question to Michael because I was like, "What's going on here?" And apparently you can do it either way, either giraffes or giraffe.
Ben: Well, I have a question. Aren't there telltale signs of singeing? You know, wouldn't their eyebrows be gone or something? You know?
Amory: Yeah, if, say, these giraffe were struck by lightning — I'm going with the no "s" plural — wouldn't they be a little toasty?
Dean: So in 90% of documented cases of animal strikes, there are singe marks. There have been several cases of mass death, though, where a bolt hits the ground and wipes out, say, 300 reindeer standing nearby, which happened in 2016. Few, if any, singe marks. The electricity hits the ground and disperses through the ground, up the one pair of legs, through vital organs, and down the other pair. I know it's kind of macabre.
Regarding giraffes and this bigger question, someone on the subreddit by the name of Peace_Bringer used an architectural formula to calculate the likelihood of a strike based on height and width alone. I thought this was pretty cool and complicated. I didn't understand it, but they calculated that a typical giraffe is 35 times more likely to be stuck than a zebra.
Dean: But again, that formula is for buildings. And it depends on where the giraffe is too. Several anecdotal cases I found were about zoo giraffes in Florida, which is the lightning capital of the U.S., so less of a surprise. It's much more lightning-y there than, say, South Africa where Gina and Gabby were.
People in the thread say, most importantly, you have to take a step back and look at the biology, the ecology. This one person suggested that because giraffes have long necks to eat from trees, they should be protected from lightning by those trees.
Amory: Oh, that's true.
Ben: It's tricky, too, because, like, giraffes might be more likely to be struck by lightning, but zebras are more likely to be behind bars.
Amory: Oh, boy.
Dean: I asked Michael about this sort of line of thought. Like, they're tall, the trees, so aren't they protected? And he pointed out two major flaws that were interesting to me. First, it's actually not a given that giraffes have long necks for eating from trees. Scientists say that that's just one hypothesis.
Dean: Another is that they can see things from far distances. So that helps to keep them, you know, from being attacked by, you know, various things.
Michael: And then one of the ones that has a bit more traction lately is what's called the "necks for sex" hypothesis.
Amory: Necks for sex.
Ben: Tell me where to buy that t-shirt right now. Take my money, please, for the "necks for sex" t-shirt.
Dean: So the way this works is it's actually like males battling each other for mating partners.
Michael: They'll line up next to each other, and they'll swing those long necks and those big, heavy, bony skulls, almost like a mace, like a ball and chain, and just wallop each other. And the animals with the heavier heads and the longer necks obviously can generate much more force and can do much more damage. All that energy is just concentrated on those ossicones, those almost horn-like protuberances they have. It's really pretty violent, but the animals with the longest necks can often do the most damage.
Amory: Oh, OK. I've been doing it wrong. (Laughs.)
Dean: Michael also pointed out that giraffes live in pretty diverse places. Forests, yes, but also open prairie, shrubby rock-land with very few trees, which was the case with Gina and Gabby. Michael also told me he's never seen a giraffe lie down in storms. They just kind of stand around and bear it. So, you know, they might very well be more vulnerable.
At the same time, one thing that I thought was really cool that I got from the subreddit. Relatively speaking, giraffes' natural habitat isn't very lightning-y. If you look at a map of where lightning strikes are less common in Africa, and then you look at a map of where giraffes historically lived, they line up pretty exactly.
Amory: So that's not a coincidence? That's giraffes knowing what's up?
Dean: I mean, it's most likely, what Michael called "correlated covariates."
Michael: So if you look at that map of lightning strikes, you know, the most intense areas were over the Congo, over the Congo Basin, which also corresponds with some really, really dense forests and some rainforest areas. So it might not necessarily be that they're avoiding lightning strikes. They're just trying to avoid other things.
Dean: But you've got to see these maps. They're — like, you could lay them right over top of each other. They're pretty cool.
Dean: OK, So let's go back to Gina and Gabby, Two tall gals caught in a thunderstorm, open brushland, few trees. After a necropsy, the researchers determined that most likely, yeah, it was lightning. A bolt probably hit Gina in the ossicone and then traveled down through her body into the ground and then back up into Gabby. Either that or it bounced off Gina and hit Gabby. A quick, tragic end.
Amory: Wow. It ricocheted off the ossicone. That's quite a concept.
Dean: But I have one more point to make that didn't come up in the subreddit, and that is the real threats for giraffes.
Michael: Yeah, so lightning strikes might not be a big threat to giraffe, but giraffe do face some significant threats across their range. By our best estimates, across all of Africa, there's about 117,000 giraffe left in the wild. To put that in context, that's about one giraffes for every 3 to 4 African elephants, for instance.
Dean: Tall as they are, lightning is a minor threat to giraffes. Even the ones I mentioned who died by lightning in those preserves and zoos in Florida, I would argue that they didn't really die because of lightning. They died because they were in the wrong place at the wrong time. Because for centuries, giraffes have been pushed out of their habitats, mostly by human development. People need space, but giraffes need space too. And those spaces for giraffes are shrinking. They're becoming more fragmented. Michael's main job at the Giraffe Conservation Foundation is not to think about lightning. It's to secure safe, natural homes for these giraffes so they don't all end up in zoos in Florida worrying about lightning or something like that.
Amory: Dean, thank you for this tall, tall tale.
Dean: Yeah, thank you.