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This episode is brought to you through a collaboration with the Smithsonian's National Museum of Natural History in Washington
DC, and the Field Museum in Chicago, Illinois.
Emily: We're here at the
Smithsonian's Whale Warehouse. It's the largest collection of whale material found anywhere in the world. And, when I say the largest,
I mean the largest!
[Emily VO] The Whale Warehouses are located at the museum Support Center in Maryland, about 45 minutes away from the Smithsonian's location on the Mall.
It's actually two giant warehouses that house both extant and extinct
specimens. With over half a million square feet of storage space, the Museum Support Center is home to some of the largest specimens ever collected,
like the 23 foot-long right and left jaw bones of the largest blue whale specimen in any museum in the world.
Today we're going to talk with Curator of Marine Mammals, Dr. Michael McGowen, about cetaceans - marine mammals
like whales, dolphins, and porpoises - and see how the Smithsonian's Natural History Museum is using their collections in
unexpected ways to better understand this diverse group of animals.
Michael: First, I just wanted to show this sort of generic bottlenose dolphin that's in all of the aquaria that people
are really familiar with, and compare that to all these bizarre forms over here. So these two guys right here
These are different River dolphins,
so this is an Amazon River Dolphin, as well as an
Indian River dolphin. And, they're actually not that closely related to one another, but they seem to have invaded river systems separately.
Emily: So this is a case of convergent evolution?
Michael: Yes, it is. So, the invasion of rivers
is an incidence of convergent evolution. And, the really bizarre thing with the Indian river dolphin is that has these growths on the skull,
which some people have interpreted it as an adaptation for
navigating in marine environments, where they can't really sense where they're going with vision.
So, they use their echolocation and it reverberates off the bone (Emily: What?) and focuses it so that they can see through the water,
through sounds. Bottlenose dolphins have echolocation as well, but they don't have these strange bony
protuberances. So they can still use echolocation but they focus it out, broadly into their their environment. Emily: Gotcha.
Michael: So this is in the category of bizarre things in the collection. And, this is a skin of an Indian river dolphin.
What we can do today, is sample DNA from things like specimens like this and get an idea of
genetics in the past. I mean, this was collected in 1910 and we can compare it to
this species today and, for instance, see if there's a reduction in diversity. Or, in the case of rare specimens,
this might be one of the few specimens left of this particular species outside of India, for instance, or Pakistan.
Emily: So, that's a great example of how when this thing was collected and prepared for a museum,
it wasn't clear how it could be used in the future,
but now, thanks to technology and
advancements in DNA, you can you can make use of it in a way that was not predicted before.
Michael: Exactly, and we can do that with bone as well. We can get DNA out of bone.
So, all of these specimens right here now become genetic repositories of
specific points, and specific places, all over the globe
into the past. Emily: That's pretty mind-blowing. Michael: It is pretty mind-blowing. Emily: That's pretty amazing.
Emily: Can I smell it? Michael: Sure! Emily: Is this weird? I'm sorry.
Michael: It's not weird at all. I mean the smell of marine mammals is lovely. Emily: It smells just like leather.
This smells just like shoes. Michael: Well, it's made out of a lot of the same material that
our skin is. Emily: This smells pretty good.
Michael: So this is a pygmy sperm whale. They probably have some of the most asymmetric skulls
within cetaceans. So this is their nasal passage right here, so it goes up to the blowhole. And, you can see this side is much
larger than this side, and that's again, because of echolocation. When they emit these sounds
through their nasal passages, they're able to tell the direction of sound.
(Emily: What?) So, they can tell if a fish is coming towards them by this asymmetry.
Emily: That blew my mind! Michael: And, these animals are really bizarre. They also have an
anal sac, that they can squirt ink out of.
Yes, it's really, really bizarre! Emily: Hold up, like a squid? Michael: Like a squid! They feed on squid and people think that they
actually save some of the ink and use it to squirt out at predators. Emily: Wow! I had no idea!
So these guys are just weirdos? Michael: They're weirdos, yes. So, cetaceans have evolved a lot of bizarre
tooth morphologies, and (Emily: Like this guy!) one example is a narwhal's tusk,
that I'm sure everyone is familiar with, because everyone's obsessed with narwhals these days. Emily: [laughing] Yeah!
So, the tusk is, for the most part, found in males, although 10% of females have a tusk.
One of the interesting things is that they use this potentially for male-male competition,
although it's not really known what they use this for -
although there's some other theories like detecting salinity, or using it as a sensory organ. Emily: But nobody really knows for sure?
Michael: No one really knows for sure. I mean we can observe how it's used,
but testing why it evolved is sort of a difficult question to get at. Emily: Mystery of the universe.
Emily: So, what is this thing?
Michael: So, this is a model of a different species called the strap-toothed whale and their tusks actually grow together and completely
enclose the mouth. It can only open its jaw, just a little bit. Emily: How does it eat anything?
Michael: Well, it feeds on squid, so it just sucks the squid in, and so it doesn't really necessarily need a huge gape.
Yeah, this is just one of the more bizarre cetacean morphology. I mean there's a lot of them. Emily: That is very weird.
Michael: They're a very weird group of animals as far as teeth goes.
Emily: So, we were just talking about sort of the diversity of cetaceans themselves,
and we're obviously here in a museum collection,
but we don't just look at the skeletal material when you have questions that you need to answer.
Michael: Yeah, so I just brought out a bunch of different other things that we might collect.
One of the things that people might be aware of is
baleen. So, a lot of the really large whales
don't have any teeth and they feed by filtering through baleen. Emily: That's what this is? Michael: That's what this is.
And, as you can see on the side here,
there's lots of different plates. The water comes through here, and then it gets caught in this fringe-like stuff.
Emily: Hair-like stuff. Michael: Yeah, hair-like stuff, right there. Baleen is one of the different substances that we can use to tell about the life history of
a particular whale. What we know is that
the baleen grows incrementally throughout the lifetime of the whale, so by drilling at different time points we can get a
picture of what the whale was doing at that point during its lifetime. Emily: Wow!
Michael: So you can look at hormones, you can look at cortisol levels (so levels of stress),
isotopes to tell what it was feeding on, or where it may have been feeding. And, we can actually go back in time to
baleen specimens that we have from the 1800s and even look at
what whale life was like back then. Emily: That's amazing! So it's like a time machine through the mouth of a whale? Michael: Exactly, a time machine.
Michael: Yes, yes.
Michael: One of the other pieces of a whale that we can use to study about their life, is their earwax. Emily: Their earwax?! Michael: Their earwax!
So, it's not the same as our earwax, but it is a
lipid-like structure that exists in the ear canal of a whale.
Incrementally, through the life of a whale, different layers are put down so we can actually use this to age really large whales.
Emily: So it puts down layers like a tree, like the trunk of a tree?
Michael: So this is a whale's tree-ring, basically. Emily: From its ear canal? Michael: From its ear canal, yes.
Emily: That's a little gross, but I'm okay with it.
So in this sort of smorgasbord of interesting whale artifacts, we also have this rather fragrant
piece of what looks like resin. What is this? Michael: So this is ambergris, and this is from the
intestinal tract of a sperm whale.
And, even today this is used in perfumes because this actually smells wonderful. It smells very musky.
Emily: Admittedly, it does smell really good.
It kind of smells like sandalwood or like, uh, like an earthy, sort of tree-like smell.
But I I couldn't picture...
well, I would say I can actually picture myself going on a beach and picking up something and being like,
"Hmm, yes, I enjoy that smell". Michael: Yeah, it's basically
condensed waxy whale poo.
Emily: Oh, cool. Well, that's a way to describe it. Neat!
Emily: So we've talked a lot today about the
diversity of whales, and the availability of the their specimens in collections like the one here at Smithsonian, and
we have this last little specimen to talk about, which I think hits it home why it's so important that these collections exist, and why they're
available for research. Emily: This is a species called the vaquita porpoise.
It lives in the Gulf of California and Mexico and at the moment, there's only 17 of these guys left. And, you know,
this is sort of a cautionary tale. But at least we have this the museum so, you know, 100 years from now -
I mean, hopefully they won't go extinct - but if they do we have
representations of them in the museum. Emily: And this little skull can help answer questions about an organism that might not be
available the study in the wild. Michael: Exactly! And, we don't know what interesting new scientific
advances are gonna happen, and what information we could actually get out of this skull. When some of these things were collected in the
1880s they had no clue that we could get DNA out of them, or what DNA was,
or things like, isotopes, or getting hormones out of baleen, but it's nice that all this stuff is
here. And, you know, every single one of these specimens, no matter how old, are valuable.
Emily: Thanks museums!
Emily: It still has brains on it!