You're listening to Weird and Dead, the paleontology podcast
that tells evolutions most embarrassing and bizarre
stories. I'm Megan Weatherell.
And I'm Amy Atwater, and we are two living scientists who are
weirdly excited about dead things.
On this episode, we'll talk about what exactly an egg is,
what sort of animals have them, including why some mammals do
and some mammals don't. And spoiler alert, I have a
fantastic. Placenta instead.
And of course we'll answer the age-old question, Which came
first, the chicken or the egg? Like always, our podcast talks
about some disgusting things, so definitely don't eat while
listening to this episode and check the warnings in the
description. Today we're talking about things
related to reproduction, specifically eggs and eggs in
the fossil record. When did they happen, why did
they happen and who, if anyone cared for them?
Which leads us to, I think, starting with a no brainer
question to get us going of Megan, What came first, the
chicken or the egg? Well, thank you, Amy.
I'm glad you asked, but it is obviously the egg since that was
around for a very, very long time before chickens.
So eggs evolved a very long time ago.
But chickens have a very special type of egg, their eggs
basically just like your eggs, just like reptile eggs, just
like mammal eggs, whether they are real eggs or not, get
dressed up in a series of additional membranes.
So they're kind of like Victorian style where they have
all of these additional layers. So an egg that has all of these
additional layers is called an amniotic egg.
And amniotic eggs are something that links a lot of the modern
vertebrate animals together. And apart from things like
frogs, which lay gelatinous eggs, so amniotic eggs, we
diverged amniotes as a group around 310 million years ago.
That's when reptiles split off from the things that would lead
to mammals. So eggs have actually been
around for a very, very long time.
Way before the chicken, that's what you're saying?
Way before the chicken. So chicken eggs are kind of the
quintessential amniotic egg. They're the thing that we think
of the most. They have a hard, calcareous
shell on top of them, which is a little bit different from other
eggs, which are more leathery. And I'd like to give you a
mental picture right now of what chicken eggs look like inside of
the chicken. Are you prepared?
Yeah, I mean, I like to only think about them on my breakfast
sandwich or like full of chocolate that aren't real eggs
and hidden somewhere. And my mom, I'm like way too old
to go on an Easter egg hunt, but she really wants to see it
happen. So she puts 20s in the plastic
eggs to convince me and my stepbrother while we're in
college to go to an Easter egg hunt.
It was awesome. We got a lot of bar money.
It was great. Wow.
That's what I think of when I think of eggs, eggs, eggs, eggs.
Yeah, chickens don't lay hollow eggs or eggs that you can fill
with 20. I guess you could fill them.
With that would be really difficult though, 'cause I know
with blowing eggs it's like very small holes in them.
So I don't know how you'd get the 20, like, rolled up into the
egg. It would be cool, though.
It'd be cool. Anyways, OK, so chicken eggs.
They take about 26 hours inside of a chicken to go from like
beginning egg to exiting the body egg.
So on the ovary of a chicken, I want you to imagine the
slimiest, wettest looking yolk that you can imagine.
No what, No whites. Those get added later.
It's basically a cluster of yolk grapes on a pink fleshy ovary.
I see how this is going to start.
Wonderful. And they are.
However, however big you think there are, they are go bigger.
They're bigger than you expect. So it is almost full yolks.
They have thousands of them forming at different levels.
But the the ovary that I'm looking at in particular has
like 2 super big ones that are ready to egg up and then
everything else is like a slightly smaller size or has a
lot of variety in there. Amy, do you remember the Jelly
beans that are covered in nerds that are like encrusted that you
get Oh my God, that you're actively eating right now?
Yeah, they look like that. We didn't plant this, but I it's
after Easter. They're all on sale.
She knows they're my favorite. I'm gonna eat one in honor of
this disgusting description. Yeah, yeah.
So imagine that. But it's like popping inside of
your teeth. Like a gusher.
Yeah, a. Yolk gusher.
A yolk gusher. I mean it's.
Always really like. Nutritionist.
Is that a word? Yeah, yeah.
I mean, if you ate a chicken ovary, you probably have some
pretty high cholesterol. OK, so there's just like, so I'm
kind of envisioning like, I don't know, almost like a
fiddlehead Fern, you know, as they're like unrolling.
No, no no. That sounds way cooler.
Instead it's like migrating, right?
Like they so like there's the the big dollops of yolk at the
top, the ones that are ready to fall off and go into the
fallopian tube and do whatever fucking other shit they do
afterwards. It's like big ones at the top
and then medium ones and then smaller ones and then just
smaller and smaller and smaller till they're like pimple size
and pimple colored. I do love a runny yolk, I'm not
going to lie. Yeah, so.
It's so gross to me. So gross.
So the yolk of the egg is the more nutritious part, which is
why if you eat like an egg white sandwich, it just tastes like
sadness. And the yolks themselves are the
the starting point of the egg and those get passed down
through their fallopian tube or ova duct I think is what it's
called in a chicken. I don't think they have
fallopian tubes and so they're ova duct is where things like
all of these additional Victoria level membranes are being put on
top of it. So you get all of these
additional membranes getting wrapped around this beautiful
little egg. Which is why, even though it
takes 26 hours for an egg to be formed, there's about a 14 to 18
minute window in which it can be fertilized.
I was wondering, I was like, when in this journey does the
sperm come into play? Well, just like I guess with
most reproductive acts, it has to happen before it gets all of
the additional clothing layers back on.
Yes. Once the yolk plops in, you got
to get fertilized before you start forming like a calcareous
shell and so that initial phase really is pretty quick.
So that's why you have a very short time window as a rooster
to make a fertilized egg. I don't know if chickens can
hold the sperm inside of their body, probably lots of animals
can, so they might be able to like save it for the next time.
But regardless, very short window it takes.
Putting a calcareous shell is the longest time period, so it
takes like 20 hours I think to put on the actual like egg shell
coating. So with chickens, do they end up
stopping to lay more eggs if they have a fertile bunch?
Like we raise chickens to just be constantly producing eggs?
What about like other bird? Like I mean don't.
Did Did I get a biological cue where they're like, OK, stop, Or
else they would just be like, constantly covered in little
baby chicks at slightly different stages of development?
Yeah. So I think they basically have
like a set number that they produce and then sit on.
I think it's like 12 to 20 or something.
And so once they've accumulated that number of eggs, they will
go into kind of a brooding mode. So it's not infinite eggs if
they're allowed to brood and raise chicks.
So us taking their eggs all the time is why they are still.
Got to start over. And more eggs because we keep
destroying their sand castles. Wonderful.
Oh, wow.
I'm still, you know, I'm still hungry.
It's still totally eat an egg. We've.
Only been recording for like 10 minutes so you just wait.
I have some grocer stories at the end.
Yeah, chicken eggs have a hard shell.
Chicken eggs also have color. So with blue chicken eggs, that
coloration is like part of the actual shell.
So that comes in super early in the process.
Whereas if chicken eggs are brown, that's actually like the
last couple of hours before the chicken lays the actual egg.
So like brown is a secondary color, which is why to make
green, you have kind of the blue color in the whole shell at 1st
and then brown is laid on down on top of that.
And that's how you typically make a green chicken egg or a
green dinosaur egg, because theropod dinosaurs and their
descendants are the only ones that are known not only to have,
like potentially chicken shell style eggs, but also colored
eggs. Turns out Dinonicus had
blue-green eggs. As said, a lot of oviractors and
trudons. That's so cool because you
remember everyone, birds are dinosaurs.
This is not a question to be debated.
We're not up for that. We also don't really care that
much except for when it's interesting.
Yeah, when I think about like turtle eggs or crock eggs,
they're all just like that kind of white.
And then those are also tend to be like a softer shell too.
So that's another thing that divides like the birds from some
of the reptilian scum. Tell us a little bit more about
what eggs and dinosaurs look like.
I have actually found Dinosaur egg before.
It looked fairly unremarkable. I mean, it was really.
Really cool. Thanks so much.
I mean they were cool. One side was a little bumpier,
one side was a little smoother. What I will say is that dinosaur
eggs are one of probably the number one pseudo fossils that
us paleontologists deal with, with the general public or just
with each other. I think that's where I've heard
a lot from folks. It's like I found a dinosaur
egg. It's like up there with finding
a meteorite. Like it's never a meteorite.
Sorry, it's just, I mean, technically, yes, occasionally
it could be a meteorite and it could be a dinosaur.
But honestly, if you're finding a rock in Oregon and you think
it's a dinosaur egg, it's not for so many reasons that we can
go into. So all those people who love to
DM me on social media, joke's on you.
I never answer my DMS and want to know if this is a dinosaur
egg. Let me just tell you right now,
it is not a dinosaur egg. We had these limestone
concretions in Big Bend National Park where I worked that would
kind of dissolve away and they were very rounded.
And so it was almost like you could look in them and see
little baby dinosaur bones because of just the dissolution
of the limestone. And oh so many times at the
visitor center, People like we. Found.
Dinosaur eggs and it's like you drop some hydrochloric acid on
it and you're like, Nope, it's not.
But anyway, I digress. Dinosaur eggs are really cool.
The ones I found we're going to talk a little bit more about.
We do actually know who laid those eggs, which turns out to
be really, really hard to do in paleontology because you can't
just watch the Troodon lay an egg in real time.
They they happened, you know, 75,000,000 years ago.
So it's really, really hard if you have just an isolated egg to
match it with a dinosaur. Or to match it with some
ambiguous cloaca, You can't. You can't find, like shape
matches. Cloaca, by the way, is the
unidimensional opening that dinosaurs and chickens use to do
everything. It's just one hole.
Oh yeah. I'm so glad you've mentioned
Cloaca, because now I can bring the cloak to the table all day,
every day because it's one of my favorite topics in our
household. It is one of our favorite things
to talk about is Cloaca of dinosaurs and what did it look
like? Is it Shape of Water?
You know how she describes it as like it opens up and then
something comes on out with her fishy, fresh friend?
Yeah, it's great scene in the movie.
Or what is it like? And like you said, it's not like
a cloaca of any given type of dinosaur is like a specific
stamp where it leaves its mark on that egg.
And so we can't go matching up. And plus cloaks don't fossilize
because they're not. They're not Bony.
This is just. That one.
That one Cicadasaurus, or whatever it is.
Oh, is that one of those weird mummy ones?
Too A whole episode on fossilized butt holes.
I'm sure, and I'm pretty sure we have cloaca trace fossils.
I want you to imagine if you sat in the mud that was so fine it
preserved the specific anatomical details of whatever
hole was touching it. God.
Geology is magical, isn't it? Could you imagine though?
Seriously for a second, if your legacy for millions of years was
like you sitting down on like the Bank of a river totally with
nothing on your bottoms and just that that impression being
preserved for like 100 million years.
I think that's a beautiful legacy and we should personally
aim for it. However I die.
I want you to find a way to preserve my holes, my orifices.
All of them. Oh, exactly, exactly.
This trace fossils are where it's at, y'all.
It's where you can actually get some idea of soft tissue.
It's where you can get some ideas of behavior.
We'll go down that route for now.
The point of this discussion is the lack of a match of cloaca to
egg, or even dinosaur to cloaca to egg.
So there's many missing pieces here in this story, which means
that dinosaur folks that study dinosaur eggs actually have
their own naming system that's unique from all other dinosaur
names. So it's like Troodon.
Actually Troodon, we do have some connections because of
being able to identify some of the embryos.
But say like there's a bunch of like a Triceratops, we don't
have any known Triceratops eggs. And so instead they have their
own genera, which is just oh oh genera, which just is
essentially taxonomic names for. Emphasize the oh if you say that
word. It's not just, oh genera, oh
genera. Could you imagine going to one
of their talks at a conference and being like this, oh genius
and this oh genius over here would be really entertaining.
Like, I 'cause there's Ohids and oh, AIDS structures and intro
geology classes and we would always be like really into
saying that. And so most of the names for
these dinosaur egg species and an ulithus.
And again, they're not necessarily tied to a specific
known dinosaur skeleton because they don't again come pre
labeled. But this is the cloaca I came
out of. I'm assuming that most of these
dinosaur eggs, in addition to lacking the cloaca connection,
they also don't have an embryo inside, right?
So it's not like you could cut them open and be like, wow,
cool, Because eggs don't always have embryos like the chicken
eggs we eat, That's there's no bones in the chicken eggs that
we eat. So you have to wait a long time
for those to develop. So if you're preserving
something early on, there's gonna just be goo in the inside.
Right. Or I mean, what if you lay an
unfertilized egg too? You know, one that just doesn't
get fertilized. You know, like.
What if he missed that window, you know?
What was he doing? But that's exactly thank you I
that's exactly one of the reasons is because either they
need to be found in association like literally still in the
abdomen of the female skeleton or it needs to have an
identifiable embryo, which is really, really hard to do and
has really only come around in the more recent years because we
have better technology. There is a relatively famous,
OK, very famous dinosaur paleontologist who likes to brag
that he still just smashes eggs open and like looks at them with
his eyes. And this is not well received by
the Paleo community when you can now CT scan things and X-ray
things and you can syncotron things, which are all just
different ways to get images of inside the egg, so you don't
have to destroy it to be able to get that information.
And so we are able to do that now, or folks have found eggs
that have been partially eroded to expose some of that.
And then with a little bit of acid prep, you might be able to
get down to that embryo, identify what the embryo is, and
then you can understand more. But that's really rare.
There's like, really only about a dozen dinosaur species that
haven't known egg embryo, which means some of our most iconic
dinosaurs. No eggs.
We don't have any eggs from AT Rex.
We. Don't have any.
We do and they just right. We're unfertilized or gooey,
yeah? We need like this, you know,
match.com for T Rex and all of its babies anyway we don't.
You think? Happens on match.com Amy, but
it's definitely not one of the sites where you find your
parents. If you do, it would be really
bad. So I believe you're thinking of
ancestry.com 23andMe. Right.
Oops. Yeah, I shouldn't say that
because yeah, both my parents definitely met their current
spouses on match.com. But but they didn't meet their
family members, which is we. Did find a bonus
auntthroughancestry.com but again another.
Notmatch.com. My baby Atwater This is
match.com. Yeah, we do need to get
sponsored. Probably match.com will never
sponsor us. Now we do talk too much about
incest. We're already there.
Exactly how long is it?
Mark the clock. Mark the clock talking about
incest. Oh man, wait.
It is just really fascinating to to think that right?
We might have their eggs out there, but again, we don't see
an embryo inside. Maybe we haven't had the study
to look and see if there's an embryo inside it.
We've found embryonic T Rex specimens, but without their
egg, like the egg didn't preserve but the embryos did,
which is crazy too, to think about just the chances of that
being fossilized and then even discovered.
Some scientists think that it is likely because not all dinosaur
eggs necessarily were hard shell like what we've been talking
about so far. They might have been softer
shells, like what we see in turtles or crocodiles that
probably wouldn't fossilize as well, so the jury's still kind
of out on that. The other way that you would
know is if potentially the dinosaur just happened to die on
top of it for one or another reasons, right leading into
maybe your next topic. Yeah, Holla.
Like, I'm sleepy. I'm just gonna, like, die on
this nest. Thank you.
Yes, one of my favorite stories, because not only is it
fascinating paleontology, but it also just gives you a glimpse of
what happens when every paleontologist is just a white
guy. And they don't have a very
diverse set of ideas about interpreting fossil discoveries
because they all are the same. Anyway, yeah, there's this
really cool dinosaur called Oviraptor.
I should say Oviraptor. It was a relatively small
dinosaur. It was pretty bird like it had.
It's got a really silly face, looks kind of like a beaked
face, and it had feathers. But it is thought to be
flightless and it lived about 75,000,000 years ago during the
late Cretaceous. I know I have to double check
about its face. I think I'm just comparing it to
others. Yeah, they are.
One of the smashed faced ostriches.
Yeah. Yeah.
Like a lateral?
Ostrich turtle like an ostrich turtle face.
And it's interesting because they're closely related to a
bunch of other theropod dinosaurs, which are what we
normally think of as our really big, sexy, scary ones like T Rex
and Allosaurus. And then these later lineages of
theropods are just these weird bird things that are really
adorable and awkward. And they always display them in
museums with, like, their arms out to, like, show that they
would have had wings. But I think they all look like
they want a big hug. And I just want, I like, I'm
always like, I wish I could hug you, 'cause they're just can't
stand it there, you know, arms out.
Like, I'm ready for it. So Oviraptor is one of these
weird theropods that is Super Bird.
Like it was discovered for the first time in the early 1920s by
a bunch of dudes who were working with the American Museum
of Natural History in Mongolia. And they found a skeleton of a
small dinosaur on top of a dinosaur egg nest in the Gobi
Desert. And when they brought news of
this discovery and the evidence back to the United States, they
took their discoveries to the president of the AM NH at that
time, Our friend, the one and only Henry Fairfield Osborne,
don't. Call him my friend.
Do not subscribe to that. But all the material that we get
from this one idiot, he's not a total idiot.
He just did some really dumb stuff anyway.
And one of my favorite Henry Fairfield Osborne stories is the
fact that this is the guy who brought to the world Nebraska
man, Oh no. Which is literally when he was
brought these, like, I think they're pig or peckery teeth
molars, and they're from Nebraska.
And when he saw them, he was like, this is Hesperopithecus,
the Western ape man, not their pig.
It's. Not their pig.
Yes, with no other lines of evidence that somehow a plio
Pleistocene ape got to North America.
I guess maybe he rafted. We don't know it.
It's just like this, very not well supported.
And if he'd, you know, looked at some other samples, he probably
would have concluded much earlier on that they were from a
pig, not from Bigfoot of the Plio Pleistocene of Nebraska.
However, that's not how it played out, and I just find that
hilarious that yes, there has been a hypothesized humanoid to
evolve in North America, and it's totally BS and it's because
of Henry Fairfield Osborne. So this genius gets handed a
whole bunch of dinosaur eggs with a dead dinosaur on top of
them. And thanks.
What? He looks at them and he's just
brilliant. So he's going look at the
proximity of this dinosaur's cloaca to the nest.
No, I'm just kidding. You didn't say that.
This president of the AM and H looked at the proximity of the
dinosaur to the nest and he saw that they had these long slender
fingers with some claws and decided obviously this dinosaur
had died trying to steal and eat these eggs.
And so he named it oviraptor, which literally means egg
Caesar. And he was convinced that they
loved eating eggs of this ceratopsian dinosaur there
Proceratops. So think of like a really early
Triceratops cousin, and they were just like, Yep, look, all
these Proceratops eggs are just being mowed down by these
oviraptors. It's just an oviraptor grabbing
like a last minute snack as it runs away from what other
whatever geological event is about to kill it.
Exactly. It's like, look at the sandstorm
approacheth must, must preserve for the long storm ahead.
So it wasn't until the 2000s, 2010 or something like that the
paleontologists were able to actually identify an embryo,
going back to the importance of embryos in one of these mini
nests that have been discovered and discovered that no, it's an
oviraptor embryo. This wasn't a murderous, violent
egg stealing monster, it was just evidence of dinosaurs that
actually cared for their young, sat brooding on their nests and
gasped parentally cared. Which is totally contrary to
these dudes thinking like obviously they were trying to
steal and eat these eggs instead of assuming, like maybe they're
trying to care for them. So that's just a just an
astounding story. This mental image of an
oviraptor sprinting away from like a plume or whatever, and
the face plants on to a nest and.
That they keep founding it like that's like they keep finding
the same founding it. They keep finding the same
association. It's like if we just like had
like a tray of popcorn or something, and we just preserve
face down in the popcorn, like that's what they're expecting to
happen, not just once, but multiple times.
Yes. And it's just such good images.
And I love again that there's this idea of, oh, not that, you
know preservation is a weird thing.
Do they have any idea that they're about to die?
Probably not. But in this world, you know,
like, oh, they were about to steal it in the storm.
Doesn't it make more sense that a parent was like hunkering down
to take care of its it's lineage and it's it's eggs and it's
final moments? Not.
Like hungry eggs that way. I don't eat eggs by falling full
force in the chicken coop onto the eggs and like, putting my
wings out to hug them. That's not how anybody eats
eggs. Like, that's.
Yeah, it seems like maybe, yeah, brooding chickens is just.
Like bobbin for eggs, right? They're not.
Yeah. And I have a feeling that this
trope is going to come up a lot throughout this podcast of how
we've interpreted certain behaviors or certain functions
and anatomical features. And it's funny how often it goes
to violence and why maybe they were trying to take care of
their babies. So that story actually, I mean,
for literal decades we just assumed that this was this egg
thief dinosaur. And it really wasn't until like
the past 20 years that we've been able to see that, no, it's
actually some evidence of parental care.
However, that wasn't the first time that parental care has been
identified in dinosaurs. We actually had the first
evidence of this back in the 70s thanks to fossils preserved at
this awesome site called Egg Mountain in northern Montana.
This is where I have been lucky enough to go find dinosaur egg
shell frag I'm. Impressed by them?
I mean, I think I still got a little emotional because
anything can make me a little emotional.
It's not like, again, it's not like you find a perfectly
preserved egg egg sometimes you do if you see evidence of some
egg shell float on top underneath, sometimes there
could be more better preserved eggs and that is how we have had
some good luck with eggs, a couple different types of eggs
at Egg Mountain. And so the site is from the Two
Medicine Formation, which is a late Cretaceous site, our
formation time period. So we're talking about
76,000,000 years ago, so before T Rex and Triceratops, but after
Stegosaurus and I, I some other ones from the Jurassic, like
Allosaurus and stuff like that. Actually two women were two of
the main discoverers of this in the 1970s, Marion Branville and
Laurie Trexler. And they found these dinosaur
eggs and baby bones essentially. And what was really significant
is not just embryonic like bones from the eggs like we've been
talking about, but also of nestlings, like young dinosaurs,
not from the egg, had fully hatched but weren't out on their
own. You know, they were still being
clearly cared for by the parents beyond hatching, which was
really, really significant and unheard of at this point in
dinosaur paleontology. They did end up naming this
group of dinosaurs Myosaura, which translates to the good
mother lizard, which is a throwback to, again, the fact
that they obviously cared for their young.
And you can go see this first Myosaurus specimen on display at
the Montana Dinosaur Center if you have a reason to go all the
way up there. Myosaurus Oviraptor.
These are unique stories amongst dinosaurs because we don't
necessarily think of reptiles as being especially attuned to
parental care. You know, that's something that
we think about more with mammals.
But how do eggs and mammals work out for the topic of what we're
talking about? I mean, do we like, I I know I
technically have eggs, but like, talk to me.
What are mammal eggs like? Surprisingly, the topic of eggs
is very relevant to mammals because mammals do have eggs.
All female mammals are carrying eggs.
It's just that they look a little different in placental
mammals. So things that have a placenta,
so things like humans, cows, most of the things that you can
think of as mammals if you don't live in Australia, because there
are three broad groupings of Mammalia.
There's placentals, which is what you're probably most used
to. There's marsupials, which are
the things that you see in Australia.
They've got the pouches, things like Kangaroos.
They're so cute. They're.
So cute. And then monotremes, which are
also in that area, are you not going to say that they're super
cute? I mean, that's not your visceral
reaction. They are super cute.
I I just saw on social media this week #monotrem dream and I
just my day was made, you know, I was like, who are these people
and are they my friends yet? If you think like that, yeah.
We should hang out. So monotremes are one of the
they're the only mammal that still has external eggs, because
the eggs in marsupials and in placentals, they undergo some
other stuff that Amy will talk about in a second.
But monotremes, which are things like platypus, platypus, don't
say that. No Platy Platypi.
Let's just not put an ease at the end of that.
I didn't know. Well.
Platypi fever ducks and echidnas, which are spiky oh
weird looking creatures with like a pill.
There's so weird and their back legs are like backwards, it's.
So weird I've seen. One once and it was the
highlight of my life. It was amazing.
So these are mammals. They still have hair, which is
something that all mammals share.
They have milk, although they don't have nipples.
They just like exude it from a patch of skin on their belly.
So that's the other thing is that monotremes, in addition to
laying eggs, they cannot suckle. So you cannot feed an orphaned
platypus using like a bottle. You have to put it, put the milk
out on your hand or something else for it to suck it up off of
the patch because that's what they're used to doing.
So imagine that, like, imagine you produce milk the same way
you produce sweat and like you just had more from one
particular part of your body. And that's kind of what
monotremes do. Oh, I also like when you say
like, they don't suckle, it's like, right, Well, look at the
bill of a platypus. And I'm like, yeah, no, I don't,
I don't like what nipple looks like that match.
We're talking about matching anatomy here.
Like, how does that work? It's.
Long and flat. Like a fissure instead of it
being like a volcano. Oh God.
OK, horrifying mental images are abounding in this episode.
You're. Welcome.
Yes. So in addition to having weird,
leaky monitoring milk patches, monitoring dream monitoring
dream, they also do lay eggs. So there's two species of
echidna and there's one species of platypus, and the platypus
lays the eggs and then kind of lays on them to incubate them.
Or you know, of course, if they were found in the fossil record,
they'd be perceived as eating them.
But they do lay really small eggs.
They're like 2cm long. So they're really tiny.
Echidnas will lay their eggs. And then echidnas actually have
a pouch, sort of like marsupials.
And so they, they tuck the eggs in their pouch.
So the eggs come with them. They are the nest, which is
interesting. See, why do we celebrate the
Easter Bunny when we already have an mammal that's already
carrying its eggs around and is super adorable and has a tongue
that's at least the exact same length of its entire body?
I mean, that's cooler than the Easter Bunny.
Well, and I mean, Easter is like ducks and rabbits, and an
echidna is kind of like those things with spikes.
With a hedgehog? Yeah.
Echidnas. Totally underrated.
Totally. We have a We've got all sorts of
stories about a kid. I'm sure we will be sharing many
Echidna facts. Because they got some funky
junk. Yes, so modest shrimps do still
lay eggs. The eggs that are in placental
mammals and marsupials are a little different because they
don't develop some sort of shell necessarily monotremes.
They have a little leathery shell, sort of like a turtle
egg, and they also have a pretty like substantial compared to
other mammals yolk. So there's a yolk in a monotrem
egg which will be important later.
So in placental mammals, I just want to reassure you because
while I was doing research for this, my immediate thought was,
wait, what happens to our egg shell?
Is there an egg shell inside us? No, there's no shell.
Whatever reason echidnas they have to kick the shell out of
the pouch. But like they have a shell but
you, there's no shell inside of you.
We're shell is and we actually don't have yolks.
Really. What happens to eggs in people
and other placental mammals? You first start with a very,
very, very small yolk sack, even in humans, that then over time,
as the placenta and umbilical cord develop, the yolk goes
completely away because the baby is able to get all of its
nutrients and send all of its waste via the placenta and the
umbilical cord. So that is what makes placental
mammals so special is the presence of this organ that we
make literally just for birth. We create an organ.
And here's slippery meat pancakes.
Spongy. Spongy.
Slippery. I have slipped on them so.
Sheep. Sheep related, sheep related,
I'm not. To explain that out of context,
that is just. You know, maybe we should.
I know you're a doctor, but I know you're not that kind of
doctor. Yeah, I'm a human doctor and I
love to just tear out the placenta and then just play down
the hallway. Slip and slide.
I've helped out on sheep farms, and the placenta just is like a
it's like the ultimate banana peel, but gross.
So gross. And they're just all over the
farm. When it's landing season, no one
is safe. Yeah.
For females, when you're in utero, you have about 6,000,000
eggs in your ovaries that are developing around 16 weeks,
which is, you know, right the beginning of your second
trimester, you've got like 6,000,000 eggs.
By birth. You've got about 1 to 2 million
eggs. By puberty, I think you've got
about 300,000 eggs. Like, that's how you're just
like they're just popping off all the time.
They're just, you know, going out.
And then, yeah, I mean, it's by about, you know, 40 that you're
down to like less than 100,000 and then it's just downhill from
there until you hit menopause. It's just fascinating.
We are little Russian nesting dolls of eggs, whereas men just
create their swimmers like every 72 hours or something like that,
yeah. Slower than chicken eggs?
Oh, I wish I'd never seen that. You guys need something to be
grossed out by. Think about my placenta.
Yeah, so eggs are still a part of us warm blooded mammalian
types, and we have a connection to a lot of our evolutionary
history through these very important structures that
without we would not be able to evolve.
If we know what, you know, eggs of birds taste like and whatnot,
I mean, what about monitoring eggs?
Would those have been even more juicy and delicious 'cause
they're, you know, close kin? OK so I have looked into this
pretty extensively and again ruined my Google search history.
So monitoring eggs, they have eggs, they do have a yolk, but
my question was would they taste good?
Would they taste bad? What would they taste like?
And obviously you're not going to actually eat them because I
think almost all, I think all modern dreams are endangered.
So even if they weren't endangered, it sounds kind of
gross to me. But again, I've established I
don't really like eggs. So this took me down a rabbit
hole of what makes eggs taste good and also what eggs can you
eat and what eggs can't you eat. And I've got to say, it seems
like almost all eggs are edible to a certain point of
development because there becomes a transition point where
you're not just the you're not eating the egg, you're eating
something else with bones. So or not bones if you're
talking about insects. So almost all eggs are edible
except for certain, like salamanders don't eat salamander
eggs, Newt eggs are poisonous. They have cytotoxin frog eggs,
though. Frog eggs you can eat.
Do people eat frog eggs? Yes.
So people do eat frog eggs. Not like, a lot.
But frog eggs have been described in the many, many
weird places of the Internet. Object Frog eggs are described
as being tart and salty, and that seems to happen with any
sort of freshwater animal. You're getting a lot of that
kind of saltiness, and you're getting a little bit of tart.
You're getting a little bit of musky.
That's what turtle eggs apparently taste like is musky.
Don't eat turtle eggs though, guys.
Just don't do it. Just don't do.
It snakes, I guess. Snake eggs are really high in
omega-3 fatty acids, so they are super fishy.
Iguana eggs are described as pretty mild, but they taste kind
of like pasta, which makes sense because pasta is actually made
with eggs. So they kind of just taste like
mild eggs essentially, but with a worse texture.
Who's eating these eggs? Influencers.
Apparently. That's like 90% of where this
information is gone. Snail eggs.
You can eat snail eggs. It's called snail caviar.
They are salty and of course gelatinous.
Fish eggs, of course you can eat fish eggs are also largely
described as being kind of salty.
They taste briny, like the sea. I have had fish eggs, so I don't
know why I'm acting like I have never tasted them.
I have not. I will not, no.
So really it seems like it kind of boils down to some like
characteristics of the family of animal, or like where it's
living. Saltwater animals are almost
always described as being pretty salty and briny, whereas
freshwater and terrestrial animals are a little less so.
It also has to do with the amount of yolk that you contain,
so. The more yolk the better, right?
Yes, yeah. So fish eggs, for example.
Part of the reason people love fish eggs.
It's fish, it's just yolk basically.
It's like a large yolky egg. It's a salty yolky egg.
So lots and lots of yolk in fish eggs, a lot of yolk in
gelatinous eggs. So the the difference in yolk
ratio is really important. Duck eggs and quail eggs.
Part of the reason they taste richer than chicken eggs is
because they have more yolk monotremes therefore.
So Platypi, because they are freshwater and terrestrial
animals, are a little different I think than probably echidna
eggs are going to taste. But I'm going to guess both of
them kind of a little bit mild in flavor, maybe a little salty,
probably taste like shit because they don't have very much yolk
in them because mono creams they, even though they lay eggs,
the eggs hatch and then they have babies that look just like
little gummy bears like your embryo does, because they're not
very far developed and then they take care of them for a long
time after they've hatched out of the egg.
So they don't need a lot of yolk, 'cause they're not going
to be in there for very long, and they patch pretty quickly.
So monotrem eggs, even if you were allowed to eat them,
probably would taste kind of like nothing at all.
And maybe that's why we still have monotremes is because, I
mean, they got started a real long time ago.
And maybe having nasty eggs is like a good evolutionary defense
too, because then you won't have all the oviraptors falling over
onto yours too. Nobody's face planting into your
eggs. Mod of dreams.
They're not worth it. No one wants to face plant into
your eggs, though I am sure any opportunistic animal out there,
an egg generally is a great source of nutrients because it
is packed to take care of a developing embryo or it's
already got an embryo in it and it's you know like pre veal.
Yeah, yeah, yeah. There's a cut off point for all
eggs as to where you can eat them.
Well, I do think we will have more opportunities to talk about
what ancient mammals and ancient animals that that matter tasted
like. I mean, we also barely touched
milk. For sure.
So what? Its own can of weird worms.
I mean, as you were describing that all I could see was meet
the Fockers and him being like you're gonna milk me, Focker.
Like having it be a platypus being like you're gonna milk me.
So in all of the research that we did for this episode, I
didn't have any fun paper awards.
But I do want to mention some of the weirdest Google searches
that were popping up as like alternate search histories.
So. Let us let us in.
Particular order Are platypus eggs poisonous?
The answer is no. Can you eat platypus milk?
The answer is you'd have to lick it off the platypus.
What does? What does platypus taste like?
A bad decision because they're endangered.
And then some of my favorites would be do elephants lay eggs
or give birth elephant eggs? Does cheetah lay eggs?
Do antelope lay eggs? Does platypus lay eggs?
That's the only one so far that the answer is yes.
Do giraffes lay eggs? Oh my God.
So I went and looked a little bit because I was curious as to
why elephants were coming up so frequently as an egg layer.
Elephants do not lay eggs and it is because ChatGPT, which has
permeated every aspect of our lives at this point.
ChatGPT got asked by someone who posted this on Twitter.
They they asked what mammal lays the largest eggs and ChatGPT
said the mammal that lays the largest eggs is the elephant.
Elephant eggs are the largest of all animals and animals, with
some reaching up to 9 inches in length and weighing up to 5 lbs.
Wow. Yeah, elephants don't lay eggs.
I just really want to ChatGPT is not a search engine.
Elephants don't lay eggs, chat. GPT is just making stuff up, so.
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interfingering, membranes. That's just yeah, God, biology
is so beautiful, so gross.