Stingray falls pregnant in aquarium despite no male ray companions

February 16, 2024 7:36 PM

A stingray that hasn't shared a tank with another stingray for at least eight years is pregnant. First link. Second link. It is likely caused by parthenogenesis, which is a type of asexual reproduction. The mostly rare phenomenon can occur in some insects, fish, amphibians, birds and reptiles, but not mammals. Other kinds of sharks, skates and rays — a trio of animals often grouped together — have had these kinds of pregnancies in human care. To be clear, Dr Lyons said, these animals were not cloning themselves. Instead, a female's egg fuses with another cell, triggers cell division and leads to the creation of an embryo. The cell that fuses with the egg is known as a polar body. They are produced when a female is creating an egg but these usually aren't used.
posted by chariot pulled by cassowaries (34 comments total)

"We were all like, 'shut the back door, there's no way'"

Err, that strategy won't keep this type of thing from happening.
posted by Riki tiki at 7:44 PM on February 16 [8 favorites]

It’s an immaculate conception! There’s going to be a Baby Jesus Stingray!
posted by Capt. Renault at 8:19 PM on February 16 [26 favorites]

To be clear, Dr Lyons said, these animals were not cloning themselves.
OK, so they are not clones. But what are they? What does their DNA show? Are they identical twins?
posted by dancestoblue at 8:24 PM on February 16

Life, uh, finds a way.
posted by augustimagination at 8:27 PM on February 16 [19 favorites]

Big black nemesis. Parthenogenesis.
posted by fluttering hellfire at 8:59 PM on February 16 [19 favorites]

Charlotte, a female ray,
Woke up a bit pregnant one day
Ichtyology
Said "Immaculately?
Shut the back door, there's no way"
posted by MrVisible at 9:46 PM on February 16 [23 favorites]

But what are they? What does their DNA show? Are they identical twins?

At least in mammals, each chromosome is doubled, but the pairs are not identical. So each egg gets a somewhat random mix of the chromosome pairs, and I imagine the polar bodies do, too. So some chromosome pairs would be the same as the parent and others would be doubles of one of the members of the original pair.
posted by JoeBlubaugh at 9:53 PM on February 16 [2 favorites]

So full siblings then? Wow.
posted by dorothyisunderwood at 10:32 PM on February 16

In my head I'm just looping on stung ray? stuuuung ray?
posted by pulposus at 10:39 PM on February 16

I feel sort of sorry for the ray, stuck in a tank with no companions of its own species. Maybe the babies will help.
posted by Phanx at 12:23 AM on February 17 [12 favorites]

“We should set the record straight that there aren’t some shark-ray shenanigans happening here,”

shark-ray shenanigans is a MetaFilter username just sitting there for the taking
posted by chavenet at 2:03 AM on February 17 [12 favorites]

A sting ray named Mary.
posted by nofundy at 2:44 AM on February 17 [4 favorites]

"We were all like, 'shut the back door, there's no way'"

Err, that strategy won't keep this type of thing from happening.

There's no poophole-loophole when you only have a cloaca.
posted by Dip Flash at 6:02 AM on February 17 [3 favorites]

The word "falls" in the title strikes me as odd, perhaps even misogynistic
posted by falsedmitri at 7:17 AM on February 17 [4 favorites]

I was thinking about "falls pregnant", as though the stingray's aquatic companions are all scandalised by her delicate condition
posted by Pallas Athena at 7:27 AM on February 17 [15 favorites]

To fall pregnant is super common phrasing in non-american English. Strange to our ears perhaps, but not misogynistic.
posted by CheeseLouise at 8:01 AM on February 17 [8 favorites]

This same thing happened at the zoo my daughter works for, Brookfield (in Chicago)! One of the sharks in their all-female tank had a single pup and she's doing great.
posted by cooker girl at 8:16 AM on February 17 [7 favorites]

"Falls pregnant" is just like "falls ill" or "falls asleep". It just means the subject entered the state in question.
posted by The Manwich Horror at 8:18 AM on February 17 [8 favorites]

Or got pregnant going over a falls, which, I guess, could happen to an adventurous stingray.
posted by GenjiandProust at 8:30 AM on February 17 [11 favorites]

So one reason that people are not keen on the phrase "falls pregnant" is because it can be easily interpreted to mean that pregnancy is a thing or condition that "just happens" and definitely not a thing that anyone other than the pregnant person is responsible for. Like obviously the pregnant person just tripped and fell and ended up pregnant nothing to see over here just some clumsy pregnant person who knows how that happens.

This has nothing to do with the actual story about the stingray but here we are. The stingray being magically pregnant is very cool, thanks for the post.
posted by RobinofFrocksley at 9:10 AM on February 17 [8 favorites]

So each egg gets a somewhat random mix of the chromosome pairs, and I imagine the polar bodies do, too. So some chromosome pairs would be the same as the parent and others would be doubles of one of the members of the original pair.

Due to recombination, it would be more of a mix of genes. The offspring would have a mix of the mother's parental alleles, similar to the way that you have a mix of your grandparents' alleles. In this case, there are only half as many options to start with.
posted by ssg at 9:14 AM on February 17 [1 favorite]

Mod note: A few comments removed about the meaning of "falls pregnant" and a few left for context. Let's move on from that derail, thank you.
posted by Brandon Blatcher (staff) at 9:31 AM on February 17 [3 favorites]

First, let me put here that I totally love the Baby Jesus Stingray angle. You're all awesome.

But- why I'm posting and if this is considered a derail, please feel free to delete:

When exactly does nature roll dice during sexual reproduktion?

In this case, if both eggs have their RNA randomly selected from, uh, Saint Mary Stingray's DNA, and everything after that was non random, the result should always be the same no? I mean, there's still 23 sets of 2 chromosomes in each egg or not?

So maybe when the two RNAs recombine one side gets overruled by the other but... for one thing, how the hell does the left side of say egg #1 chromosome #18 know it should recombine with the egg #2 left side chromosome #18 and not any of the other like 91 candidates (including the others from the same egg)? Wait stingrays probably have a different number of chromosomes than humans but hopefully you get the idea.

When that #18 chromosome recombines with the correct partner, randomization shouldn't change much?

Or maybe I'm just totally misguided and gametes don't actually have double chromosome sets. Then it would be a lot easier to explain i Iguess?

Boy these are such a complicated origin storyies.
posted by flamewise at 10:51 AM on February 17 [2 favorites]

I'm kinda surprised some garbage AI "news bot" at Fox News or the Daily Mail hasn't yet distorted this into an article about Biden's car becoming scandalously gregnant, kinda how "Sahil Omar" is their new criminal bogeyman.

> shark-ray shenanigans is a MetaFilter username just sitting there for the taking

"shark-ray shenanigans" sounds like some Gold/Silver Age comics pelagic supervillain's whole schtick.

"...But with tech like that, you could cure cancer."
"But I don't want to cure cancer. I want to turn people into dinosaurs stingrays and mantarays."

posted by Fiberoptic Zebroid and The Hypnagogic Jerks at 11:06 AM on February 17 [1 favorite]

So maybe when the two RNAs recombine one side gets overruled by the other but... for one thing, how the hell does the left side of say egg #1 chromosome #18 know it should recombine with the egg #2 left side chromosome #18 and not any of the other like 91 candidates (including the others from the same egg)?

There are two processes in play. First cells double each chromosome (so humans go from 46 single chromosomes to 46 doubled chromosomes). Then the homologous chromosome pairs themselves pair up, so the chromosome 18 pair that comes from your dad pairs up with the chromosome 18 pair that comes from your mom. At this point, the chromosome pairs can exchange pieces of themselves. So the chromosomes from your dad will now contain a certain portion that was from your mom and so on. Then the cell has a whole complicated machinery that lines every pair of pairs of chromosomes up and divides them equally into two cells, so each cell has a pair of each chromosome (so each cell has a pair of chromosomes 1-22 plus two X or two Y). Already, we have a bunch of fairly random mixing between genes from each parent.

Then those cells do something similar again to line up and divide the chromosomes, but this time they are splitting those pairs in half and putting them into two different cells. So now you have four cells, each one with 23 chromosomes (and each cell has a different combination of chromosomes and, due to the mixing that took place in step one, each of those chromosomes is unique). One of those cells becomes an egg for females and all four become sperm for males. Then a random combination of sperm and egg join together and you're back to 46 chromosomes for the embryo.

The key point is that you only get one of each chromosome from each parent, not a pair — but that one chromosome is a mix of the chromosomes that came from each of your grandparents.

The exact mechanisms that the chromosome pairs use to line up have to do with specific DNA sequences on each chromosome that line up and bind with the corresponding chromosome and a bunch of proteins that help this process along and other proteins that make sure the division is correct and don't let the cells split into two unless everything is lined up just so. Still, sometimes things go wrong and chromosomes aren't split up evenly and then usually the new organism won't survive, but in some cases we get conditions like Down's syndrome (having three of chromosome 21 instead of the usual two).
posted by ssg at 11:50 AM on February 17 [6 favorites]

When exactly does nature roll dice during sexual reproduktion?

Look up meiosis. In ordinary cell division (mitosis), each chromosome is duplicated, and each daughter cell gets one of the copies. (Assuming nothing goes wrong.) In meiosis, which is used to make the gametes (sperm and eggs), the chromosomes line up pair by pair and exchange pieces of their DNA more or less at random before separating, that's the dice roll.
posted by phliar at 11:54 AM on February 17

Sorry but I must say it: "immaculate conception" refers to Mary being conceived, not Jesus. Or at least that's what Catholics say. I don't know if the stingray is Catholic (it's been years since I've been to a Catholic church, I don't know what their position is on such things these days).
posted by The corpse in the library at 1:17 PM on February 17 [10 favorites]

I believe most of the cartilaginous fishes are congregationalists.
posted by The Manwich Horror at 1:22 PM on February 17 [13 favorites]

I don't know if the stingray is Catholic

Can you eat them for Lent
posted by fluttering hellfire at 2:27 PM on February 17 [5 favorites]

> Sorry but I must say it: "immaculate conception" refers to Mary being conceived, not Jesus.

Whew, you beat me to being That Person but yeah.
posted by desuetude at 4:15 PM on February 17 [1 favorite]

So this is Stingray Mary?
posted by Ray Walston, Luck Dragon at 7:01 PM on February 17

Still stingray Jesus unless they can prove the pregnant stingray has never done nothing wrong her whole life, and we all know stingrays are the dastardly rakes of the sea
posted by dorothyisunderwood at 7:50 PM on February 17 [2 favorites]

Abstinence is the only effective birth control!

(Uh, let me get back to you on that.)
posted by maxwelton at 11:49 PM on February 17 [2 favorites]

When exactly does nature roll dice during sexual reproduktion?

Perhaps this is thinking about it in the wrong direction. What happens is that, well, stuff happens - and evolution is left to render whether the genetic "stuff" persists in genetic code or ... not.

A lot of chance happens and whether or not those traits become fitness-enhancing (or are just hangers-on), then they persist.

Sometimes stuff like parthenogenesis happens and there's no real downside, but no molecular cascade occurs, then it can just persist. No harm, no foul. Ish.
posted by porpoise at 12:15 AM on February 19