How a Reptilian ‘Virgin Birth’ Baffled Scientists
Dr. Kaylee Byers and Producer Phoebe Melvin share one lonely crocodile’s story that surprised scientists and sheds light on their distant relatives that once wandered the earth.
Dr. Kaylee Byers, Music, Phoebe Melvin
Dr. Kaylee Byers 00:09
Kaylee Byers, Phoebe Melvin. Nice Gene Shorts. Okay, Phoebe, what have you got for us today?
Phoebe Melvin 00:16
I want to start off by posing you a hypothetical. Do you feel that perhaps in our modern era of fast paced life, that it’s still possible to, like, truly find romance in this world?Read Transcript
Dr. Kaylee Byers 00:28
Some novels would have me believe yes, others would have me believe no.
Phoebe Melvin 00:32
Well, today I want to highlight a discovery that really goes to show that perhaps you don’t need a cozy mate to find what you need. And this story has teeth. So I want to turn our attention to a lovely lady living in isolation down in Costa Rica. Her name is Coquita, by human standards, despite her lovely little eyes, she isn’t somebody you’d want to cuddle up to. But biologists love her. And I’m going to tell you why. She’s a crocodile.
Dr. Kaylee Byers 00:43
Ouch Oh, I love her already. But what, what makes biologists love her?
Phoebe Melvin 01:17
Right? So this lovely lady crocodile. She’s been living in isolation since 2002. She was taken into captivity to a place called Parque Reptilandia. And she’s been living by herself, but somehow she gave birth to a clutch of eggs in 2018. And it’s something that scientists call a virgin birth or parthenogenesis.
Dr. Kaylee Byers 01:42
Phoebe Melvin 01:43
My friend George tells me; that comes from two Greek words Parthenos, meaning virgin and Genesis meaning origin. So she was able to have these eggs all by herself.
Dr. Kaylee Byers 01:55
So how did this happen?
Phoebe Melvin 01:56
Yeah, well, that’s the thing. Scientists aren’t quite sure exactly what is happening when there is a quote, unquote, virgin birth. But this isn’t the first time that it’s been seen in the animal kingdom. Scientists have seen it in birds, in sharks, in lizards, in snakes, but this is the first time it’s been seen in like a crocodilians. So crocodile, alligator, gharial. So this mama crocodiles living on her own doing her own thing, she gives birth to 14 eggs. And the researchers at the park are like, Sorry, what? And then they realized that not all of the eggs are viable. Only seven of her 14 eggs are capable of like producing little baby crocs. So they take the eggs, they put them in an incubator, and they really start to observe them hoping that one day soon they’re going to hatch. But unfortunately, none of them did. So…
Dr. Kaylee Byers 02:50
Phoebe Melvin 02:51
Yeah. So they waited long enough for the eggs to hatch, if they were sort of going to. And when they didn’t, they sort of pop them open, they had a look inside. Six of them didn’t have any discernible life inside them. So it was just kinda like a goopy mess. There was one that was a little bit different. The last one had like a fully formed, baby Croc inside it just hadn’t hatched. Even though it looks like it should have been able to.
Dr. Kaylee Byers 03:19
Well, that’s really exciting. I mean, it’s both really interesting. And also very sad for the little baby chomp chomps.
Phoebe Melvin 03:25
Scientists love information. So they went and did a DNA test on the one little fully formed baby Croc. And they compared the DNA from the baby Croc to mama Croc, and it was basically identical. What this is telling us is that Coquita the crocodile basically, like cloned herself to try and produce a clutch of eggs. Unfortunately, this time, it didn’t pan out. But it is the first time it’s been seen by science. And this could well be happening out there in the wild. And just no one’s ever noticed before. And maybe it will happen again in captivity.
Dr. Kaylee Byers 03:58
This is wild. I mean, it makes sense, right? That the DNA would be identical. If it’s just coming from Coquita. There’s no sperm around. So why, why does this happen? Do we know?
Phoebe Melvin 04:12
Yeah, I think there’s a bit of speculation about what the cause is. You can’t really ask a crocodile, why did you do this? But I think the the suggestion is that, you know, the advantage of being able to do sexual reproduction to breeding with a partner of the opposite sex, as well as asexual reproduction, like Coquita did, which is producing babies by yourself means that if you’re a species that’s under threat, and there’s not many of your kind running around in your environment, they’re hard to get to, or perhaps you’re really spread out in a very large area and it’s hard to find a mate. The advantage is that you could still produce babies by yourself without having to find a mate. So you wouldn’t miss a whole breeding season. You would just produce your own babies. You don’t, don’t need a man.
Dr. Kaylee Byers 04:59
So you have, you have a couple options. Essentially you can go sexual, you can go asexual, I love this for our crocodile queen.
Phoebe Melvin 05:06
Oh 100%. She’s an icon. And what it tells us is that, because we’ve now seen this in crocodiles, as well as birds and sort of other reptile species as well, is that there must be some sort of evolutionary connection between species that can do this. So birds and crocodiles are both descendant from an ancient group called archosaurs. So that’s a group that includes dinosaurs and pterosaurs. This suggests that maybe dinosaurs and other ancient reptiles alive at the same time were able to asexually reproduced so produce babies on their own. So this might give us a hint about a species that we were never able to observe in life. And how they were able to reproduce which is pretty cool.
Dr. Kaylee Byers 05:52
And you know what, exactly what Jurassic Park taught me ever so long ago, I mean, we should have seen it coming Ian Malcolm back there saying “Life finds a way”
Phoebe Melvin 06:02
Dr. Kaylee Byers 06:02
Phoebe Melvin 06:03
Dr. Kaylee Byers 06:03
So here we are. Look at this.
Phoebe Melvin 06:05
Dr. Kaylee Byers 06:05
Projection into the future. He was exactly right.
Crocodile tears each time they fall. Somehow I know, mean nothing at all.
Dr. Kaylee Byers 06:19
Phoebe, thank you for another titillating tale with teeth for us today. And it was just a really neat example of how you know our natural world can really flip some scaling assumptions on their back on things about sex, mating and reproduction.
Phoebe Melvin 06:35
100% I’m all for the girl power.
Dr. Kaylee Byers 06:50
For those of you listening, there’s a hint in there for you too, about one of our upcoming episodes on season three of Nice Genes so stay tuned. I’m pleased to say our new season will be dropping on August 22. So hit follow so you don’t miss our landing. Until then. Thanks for listening.