Hello and welcome back Shark. Here's to another episode of
Deep Dives with Sharks. My name is Alex and I'm the host
of this thing and I'm just trying to bring peace, freedom,
justice and security to my new empire of sharks.
Anyway, I appreciate y'all sticking with me while I was
gone for two months on another impromptu hiatus, but I have a
little rundown slash update. I travelled over 11,000 miles
since May 22nd through June 15th and I saw zero sharks.
So America, why are there no sharks in the middle of our
country? Feel like that needs to be
fixed, among with many other things.
But anyway, I should be done with travel for a little bit,
which is exciting, at least I'm hoping so, and I should be able
to settle into a rhythm and be more productive.
It's also been requested that we do another movie review.
So that will be coming along with, of course, our annual
Shark Week versus Shark Fest reviews.
Once I actually watch the programming because I was a
little bit busy and missed most of it.
I'm still trying to get this more uniform and still streaming
on the weekends to talk many things sharky.
So follow the links in the tap link in the description so that
you'll be able to get to all these social medias.
But here we are getting this episode out once again.
I'm very glad to have you all here now to stay up to date on
everything Deep Dives with Sharks, hit the follow button on
Spotify, Apple Music, Instagram, Twitch, YouTube, Amazon Music or
anywhere else that you get your podcasts at Deep Dives with
sharks. Feel free to ask any questions,
share any comments or any shark related content on the social
media and in the comments. And I did want to thank a couple
people that I think recently found the stream or the podcast.
I'll say as they did a comment on like every episode that they
had listened to, which is incredible.
And I do really appreciate that. And I think we're also really
close to hitting 2800 followers, which is incredible.
So I want to thank you guys all very much for all your support.
But I do have a little bit of a correction slash question corner
for this episode. I haven't asked some more
questions since last episode and I figure I'll answer them here.
So feel free to ask questions in the comments or DMS and I'll
answer them here occasionally so that every episode is in a long
question corner And then 4 minutes of sharks.
I feel like a lot of us have started listening to a podcast
and then realized that the intro becomes longer than the content
and that's not as fun to listen to.
So here we'll go ahead and we will try to figure out how to
make this nice balance. But First off, I got a question
from Ted and Georgia. They asked how many bones a
basking shark would have. As I had previously mentioned,
they have no bones besides a jaw as many other sharks.
And I haven't come across really any sharks that have bones, just
cartilage and similar structures.
But there are so many sharks to cover still, so there could be
one out there. Plus, researchers are always
finding new sharks and could discover a Bony shark.
So we'll have to wait and see. I do want to clarify a little
bit though, because of course, having the jaws and teeth count
as a bone can be a little bit confusing, especially for a
large shark like a basking shark where you don't really see their
teeth. Because whale sharks and basking
sharks appear to be toothless, but they actually have hundreds
of very small hooked teeth. They're easy to see if you're
like right next to it and like being its dentist, but of course
if you're just looking at a picture of it, it's very hard.
They don't use those teeth to hold or bite prey as they are
filter feeders, but those teeth are believed to help with
filtration. All this to say, depending on
the source, sharks will have anywhere from zero to 1 bones
depending on if they count the jaw and others will count the
teeth which gives a wide range. But yeah, they do have very few
bones, and they are pretty much made-up entirely of cartilage.
There also was another comment which unfortunately I couldn't
find but I remember seeing it. Someone asked after watching
episode 2 I believe it was that due to further research, is it
still not recommended to punch sharks?
Which amazing question and I did want to update this a little bit
and I kept forgetting so here we are.
But after looking more into it, you should never just go punch a
shark for no reason. And you should avoid touching
sharks in general because similar to dogs or other
animals, we don't know how temperamental they'll be.
So they could perceive like a touch that's just supposed to be
like a nice friendly pet as an attack.
And then they'll retaliate and bite you, which is not great.
But you should try to keep some distance from larger sharks.
And it won't be easy to redirect them with like a gentle push.
You'll actually have to have like a little bit of force
behind it. So having something to keep that
distance between you and the shark is never a bad idea.
Usually there's like shark bullies or things like that.
Those will be really helpful because it'll bite that instead
of your hand if it doesn't like where it was touched.
Now, if a shark does bite you and is holding on, then yeah,
punching it is not a bad idea at all.
Go for the parts that'll be a bit more sensitive like the eyes
or nose as the ambulate of Lorenzini will go into a frenzy
when it's touched and it can cause them to open their mouth.
Now if you get bit and the shark let's go in a swimming away and
you decide you're going to go fight it in the parking lot,
it's not really recommended because you probably already
need medical attention and that shark is not going to be in the
parking lot anyway so you're just kind of wasting time.
But the TLDR version is you don't punch sharks in general or
for fun. Try to have something to help
push a shark away if it's getting too close for comfort.
But of course, if a shark is biting you punch it like don't
just sit there and be like, well, Alex told me not to to
punch this shark, but it is currently eating my foot.
So I'll stop that. Not like you swing on it.
It's that's fine. That's the common sense here.
If you're in danger, punch a shark.
If not, don't punch a shark. There we go.
Now getting into the actual sharks for this episode.
And I did say sharks because we are, of course dealing with
another three shark episode. The first shark we're going to
be talking about is the blue shark.
The blue shark is the only shark in their genus and are found in
deeper waters of temperate and tropical environments.
They vary in size by gender, with males going to be about
1.82 to 2.82 meters or 6 to 9.3 feet long, and females tend to
grow to be about 2.2 to 3.3 meters or 7.2 to 10.8 feet long.
So they want to get a little bit bigger.
They just identify as the other gender and they change.
Not actually it's a just a little funny ha ha.
But you know, females are bigger.
They tend to have sleek bodies with a smaller dorsal fin, very
long pectoral fins and their tail is similar to a nurse shark
although closer to equal on top and bottom but it does still
have a little notch at the tip. They tend to look surprised to
see everyone's here as their eyes are large and tend to have
a people so you can see a little bit of like the whites of their
eye. Their mouth is slightly open and
they have an elongated snout. They do really appreciate that
everyone came to their surprise party and they were 100%
surprised. They tend to weigh between 27
and 55 kilograms or 60 to 121 lbs for males and for females
that go anywhere from 93 to 182 kilograms or 205 to 401 lbs.
Larger females have gotten up to 204kg or 450 lbs So which I
think it might have been one O 5 initially.
I'm not realizing that the two O 5 is less.
Anyway, I think I did my numbers wrong I apologize.
There the blue shark has five senses similar to many other
requiem sharks that include vision, hearing, lateral line
which is a sensory organ that helps detect vibrations and
changes in water pressure which is according to Google Electro
reception. So that system that allows them
to sense electronic pulses in the water such as heartbeat and
also chemo reception or chemo reception that helps determine
food sources such as fish stress juices released into the water.
They also have special eyes compared to other sharks as they
like being anywhere from the surface of the water to 350
meters or 1150 feet. So their eyes are able to adjust
to that bright and very dim light settings.
So that's also why you can see the pupil a little bit.
They are given full 360° vision vertically and up to about 338°
horizontally. So they can't see completely
around themselves, but they're pretty darn close to it.
For reference, humans have about like 180 vision I believe it is.
Think a little bit more. They cover a wide range of the
ocean, as far north as Norway and as far South as Chile.
So pretty much everywhere except for Antarctica and the North
Pole. They are mostly found in water
temperatures between 12 and 20°C or 54 to 68°F, but have gone
from 3.9 to 31°C or 39 to 87.8°F.
Which I will say Celsius makes so much more sense for measuring
temperatures. A Fahrenheit's a lot more
specific, but when I'm trying to explain to a European that it's
106° and they think that everything's just boiling, it is
pretty Dang hot out. But we're not all just catching
on fire. Well, we do have wildfires
anyway. Blue sharks, like many other
sharks, migrate across the ocean during seasonal changes, as well
as looking for more food or better environments.
They usually swim around 1.3 kilometers an hour during the
day, but are more active at night, swimming in about 2.8
kilometers per hour now. These bursts occur throughout
the water column, as these sharks will search for food in
deeper than 100 meters if necessary.
They do tend to move closer or further from the surface
depending on temperatures and if they need to warm up more, but
sometimes they do it just to work on a tan because they are
rather blue. They're not quite as blue as a
member of the Blue Man Group, but much more blue than a sand
tiger shark. Now, blue sharks tend to eat a
lot of different organisms as they inhabit many areas of the
ocean. Well, pretty much the entire
ocean except for, you know, the North and South Poles.
But they don't like the cold anyway.
They prefer squid over everything else.
But we'll also eat blanket and pelagic octopus, cuttlefish,
lobster, crab, shrimp, and many Bony fish.
They yearn for the bones since sharks don't have bones.
I've been talking a lot about cartilage and sharks recently.
I'm going to eventually get off that topic I swear.
But outside of the Bony fish, they also eat smaller sharks,
some birds and porpoise and whale blubber.
Now blue sharks benefit from pack hunting as they can stir up
a bait ball that forces fish towards the surface.
They can then catch their prey easier.
It's easier to catch things in a group versus an individual,
unless it's like a shark. They like individuals, sometimes
small fish. Anyway, there's a whole thing
like a tangent I can go on but I won't.
But you can see bait balls a lot while you're at the beach as the
water tends to look like it's boiling from the surface.
But that's just because of the bait.
The fish are all towards the surface and are trying to get
away from whatever is currently hunting them.
Now just because you see a bait ball, that doesn't necessarily
mean that there's a shark there. Other animals like dolphins or
fish like tuna will stir up bait balls while hunting.
Blue sharks are prey for larger sharks such as great whites or
tiger sharks. But I've also been haunted by
orca, which is why I'm not a huge fan of orcas because they
just eat too many sharks. But not only do these sharks
have to worry about larger sharks and orcas, but also
parasites like the tetrafyllidine tapeworm and
mammals like California sea lions, northern elephant seals
and Cape fur seals. So real quick, blue sharks, you
and I got to have a quick chat here.
You have to step it up. Great whites will try to eat all
these things and y'all are getting got by them.
So we got to work on it. OK, thanks.
Now, humans don't encounter blue sharks in the wild often as they
like the open ocean and we don't really hunt them, but there have
been only 13 bites by blue sharks on humans from 1580 until
2013. Now, since 2013 there have been
over 500. I'm kidding, there's been 0.
They're still sitting at 13 bites total.
So humans don't interact with them very often.
They have been unsuccessfully kept in captivity on multiple
occasions, but have either died or been returned to the ocean
after a few months. They are relatively easy to feed
and transports. That's not the problem.
The problem is that they don't do well with flat surfaces and
tend to injure themselves. So kind of a little bit of a
recession as like who they get haunted by and getting got by
fish tanks. But that's also why it's very
important for the zoologists and zookeepers and Aquarius in the
aquariums to know what animals they're taking care of.
Animals can be very susceptible to injury or illness and not
knowing these things can be very detrimental for the animal.
Now blue sharks are listed as not threatened for their
conservation status as they tend to do fine in the wild and they
really aren't messed with by humans.
So it's really exciting, but that's what I have for the blue
shark. Of course, any questions, any
comments, concerns, anything of that nature, you can always send
them over to me on the social media, anything in the tap link
or in the comments. Now going on to the next one, we
have the pajama shark. Now pajama sharks are also known
as the striped cat shark as they are a member of the cat shark
family. Now it gets its name from the
stripes that run down the length of its body, which mimic striped
pyjamas. And for the adults listening,
the pyjama shark did not inspire that movie that's from World War
2. And for the kids listening,
don't worry, it's just striped pyjamas.
This shark is very different from other cat sharks as it
grows to be a bit larger at 1.1 meters or 3.6 feet and around 79
kilograms or 17 lbs. Now that puts them at a very
small side for sharks as the average is about 5 feet.
So they are a couple feet shorter than that and if you're
over 5 feet tall, congratulations, you are taller
than the average shark. Now pajama sharks have a very
Flathead. It's almost like someone stepped
on their nose. They have barbels that hang off
of their nose, but they don't reach their mouth.
The snout comes almost to a blunt point, so similar to a
tiger shark, but it's much more flat.
I don't believe I've ever had to go over a shark's nostrils
before, as they usually tend to operate similar to ours, but
instead of smelling air, they smell water.
But today we get to talk about a pajama shark's nostrils because
they're different. Now they have 3 lobes, one for
in current, one for X current, and then they have the barbell
which is also part of the nostril.
And I couldn't find a whole lot on what those barbels do, so I'm
assuming they operate similar to other fish, just helping with
sensing things around them. Their eyes are horizontally
Oval, meaning that you take an Oval and you put the long ends
on the top and bottom and boom, pajama shark eye.
Now their eyes are also rather wide set compared to other
sharks. So for a little bit of clarity,
they're not quite as far apart as Sid the Sloth from Ice Age.
They're also not hammerhead length, but if you take like a
black tip reef shark and then put the eyes a little bit wider,
then there you have it. It's about how far wide their
eyes are. They have a deep Ridge that runs
under their eye, which looks pretty neat.
The pajama shark has a slender body that becomes more narrow
towards the tail. So they kind of start narrow,
get a bit wider, and then get narrow again, almost kind of
like a torpedo would. Other pectoral fins are slightly
large for their body, but the two dorsal fins are very small
comparatively. The dorsal fins sit further back
on their body, with the first one being about 3/4 of the way
down their back and the second being just before the tail.
All their fins, excluding their pectoral fins are rather small
and that does include their tail.
Their tail is taller on the top than the bottom as they are
bottom dwelling fish and usually fish that have longer tails on
top are bottom dwelling as they want to make sure they're not
going to drag their tail along the floor which could cause
injury. And then of course that can
cause so many more complications.
So just a nice little evolutionary thing to help out.
Now they have 18 to 25 rows of teeth on their top jaw depending
on the individual and 14 to 24 rows on the bottom.
The pajama shark's teeth are shaped somewhat similar to a
frilled shark where they have a longer central cusp and they
will have two smaller cusps on either side which creates a Tri
cusp and tooth. Now, cat sharks tend to have
thicker skin as they are a smaller species of shark, thus
providing a little bit more protection.
The pyjama shark, being a cat shark, also has thicker skin,
which helps to protect against predators like crabs or other
smaller fish that can't bite them.
It doesn't help a whole lot, evidently, especially if larger
sharks are able to eat them and other large fish.
But you know, at least the crab that usually goes for things
that have already died won't eat them, so that's good.
Pyjama sharks are found around South Africa, especially the
southern tip. They like waters that are as
deep as 4 meters or 13 feet, so rather deep, but they do go much
deeper, about 50 to 100 meters or 160 to 330 feet.
They prefer rocky reefs as they can utilize caves, which are one
of their preferred habitats when hunting.
Pajama sharks tend to go for Bony fishes such as anchovy or
hogfish, smaller sharks and rays, as well as egg cases,
bivalves, cephalopods and crustaceans, which most sharks
do enjoy eating. Cephalopods and crustaceans,
I'm, I mean kind of just lump them all together in that one.
They are opportunistic feeders and will take advantage of
whatever they can get, including ripping off tentacles from an
octopus or cuttlefish, which I do believe both of those are
able to regenerate those tentacles.
So it is rather kind of them to consider that it will grow back
before taking it. But they also are sort of
practicing sustainable food sourcing in that sense.
If it'll grow back, you can get it later again.
That's why you got to make sure you're doing sustainable fishing
anyway. That's dumb, but the pajama
shark has been observed ambushing chaka squid during
mass spawnings as they like to hide among the rocky surface and
wait for the squid to descend to deposit its eggs on a rocky
surface on the reef. And then they go eat them.
Of course it's always hunt or be haunted because they are haunted
by broad nose 7 gill sharks and are that sharks preferred food
source. And that also made me realize
that I'm not sure why they made the saying a dog eat dog world
because you'd never really hear about dogs eating each other,
but you always hear about sharks eating each other.
And I mean they really can't stop eating each other except
for like the whale and basking sharks.
They kind of just chill and not a whole lot eats them.
So that's kind of neat. But pajama sharks are oviparous,
so egg laying they can lay 1 egg at a time.
So there will only be 1 Bebe. Their eggs tend to be 9.5cm or
3.7 inches long and they have tendrils which are kind of like
these long strings that come off of them.
So that way Mama shark can anchor them to a rock or a plant
or something that won't allow it to be taken away by the current,
roll around or get damaged as easily.
Now these sharks do interact with humans rather frequently as
they tend to be in shallower waters and they look pretty, so
humans often want to see them. We also like catching them by
accident as bycatch and many fishers find them to be a pest
since they'll take bait right off the line.
So usually they'll see them and then kill them on site, which is
rather messed up. But despite all this, they're
listed as least concerned due to lack of evidence for population
decline, which this shark of course raised a huge question
for me. This shark inhabits such a small
area and only lays 1 egg at a time, which makes me wonder,
would they be more susceptible to rapid population decline
compared to other sharks as the blue shark covers pretty much
everywhere and it would take a lot to put a dent in their
population. Now, unfortunately, I don't have
an answer to that, so I might try to reach out to a couple
shark experts and see if any of them have a good answer for that
because I think that'd be a really interesting topic to talk
about. Yeah.
So that's what I have for the pajama shark.
Appreciate you guys checking in on that one too.
And of course, we have our final one.
Now, this one was actually requested quite a few times.
I think the most recent one was about 18 days ago.
So surprise, here it is. It's the spiny dogfish.
Now, spiny dogfish were one of the first sharks that I learned
lived in Maryland waters, which, fun fact, so do blue sharks.
So I always get a little bit excited when I see them on my
timeline or hear anyone talking about them or get a chance to
see them anywhere. It's really cool.
They also make me think of Dogfish Head Brewery and their
60 minute IPA and Sequential because I just love them so
much. Dogfish Head.
If y'all are looking to sponsor a podcast, I'm available.
Slide in these DMS. Kidding kind of.
Land Shark's also acceptable. If there's any shark related
product that is looking to sponsor a podcast, hit me up.
We can make something happen. But anyway, spiny dogfish vary
in size depending on their gender, with males growing to be
about 24 to 35 inches or two to just under 3 feet, which is
about 70 to 100 centimeters or about a meter.
And I'm still trying to figure out why they used these smaller
measures as my brain hears 24 to 35 inches and thinks that's
rather small until I realize it's two to three feet.
And I'm like, it's like half a person noted.
Which is just kind of disrespect for the sharks as well.
But these guys are mostly grey. They do have white spots along
their back though. They have two smaller dorsal
fins on their back as well. The first is dead center and
almost looks a bit like a sail with its triangular shape.
The second sits closer to the tail, but not quite as close as
the pajama shark second dorsal fin, which is practically fused
with their tail now. Their caudal and pectoral fins
are triangular as well, which is different from many sharks that
tend to have rectangular or box shaped caudal fins.
Both their dorsal fins contain a spine, hence the name spiny
dogfish. But of course, these spines
aren't just there for decoration, they're used for
defense or to impale predators. They aren't done yet though,
because the spiny dogfish felt that stabbing those trying to
eat them was not enough. They also have venom in these
spines, which is just pretty hardcore.
Now, the venom is not lethal, but it will cause pain and can
cause a predator to think twice about trying to bite the shark
again in the future. Now, if humans are to be
impaled, we could. Emphasis on could because it
varies by the individual. Experience intense pain,
swelling, and redness at the sting site.
Other options are impaired mobility, so difficulty walking,
dizziness, nausea, and abdominal pain, all of which can last for
a few days or weeks. Still can't kill you though, so
that's pretty good. But the good news is that they
cover a very small area. And I lied again, they cover a
large area. They're found in coastal waters
of the eastern US and Canada, southern parts of South America.
So around Chile, just around the tip to about South of Brazil,
the Mediterranean Sea, Europe including the UK, Spain,
Portugal, France, Sweden, Finland, Norway.
And then we also have southern Australia and all around New
Zealand. Now thankfully humans don't have
to worry about stepping on spiny dogfish or dealing with their
shark venom as they are bottom dwellers and typically reside
around 50 to 149 meters, which is 160 to 490 feet but can go
all the way down to 700 meters or 2300 feet.
Which side note, it is such a weird number to cut off the
first numbers at 149 meters or 490 feet, both for the shark if
they just don't go that extra like meter or scientists for
just not giving them that meter. But for accuracy sake, we'll
keep it right where it is. They do have some human
interaction as in Europe, America, Canada, New Zealand,
Venezuela and Chile, they are served as food, which after
looking at a picture of the dish, it doesn't look very
appetizing. So like what?
What are we doing now? This funny dogfish is served
under a variety of names, including unwitting hound shark
in Greece, pus or rock salmon in fish and chip shops across
Europe, small salmon in France, and then it's sea eel in Belgium
and Germany. So it's sea space eel, not seal,
but sea eel. They aren't only eaten, though,
They're also used in fertilizer, liver oil and pet food.
Many countries have banned the sale and trade of dogfish for
the entire species or at least limit the numbers for sale.
Meanwhile others America have decreased regulations on fishing
and drilling allowing for more sharks to be caught and sold.
Spiny dogfish like hunting impacts and are very social.
They've been counted in schools of thousands, which is one of
the largest schools of sharks I've heard of.
Now mind you, there could be another shark in larger
congregations, but for now I believe the spiny dogfish is in
the lead. Of course, correct me in the
comments if I'm wrong. I feel like some of y'all know
the podcast material better than I do, and I actually do love
that. That's pretty neat.
But little side note, I forget which factor episode it was on,
but someone commented on a detail I gave about a shark and
started along the lines of well you were kind of on the right
track and then provided the information which I thought was
super helpful. So that's of course why I have
correction corner at the beginning and I'm also more
interactive on Instagram and in the Discord as I do not know how
to reply on Spotify or Apple which is very boomer ask of me.
I'm working on it. But of course if you guys have
any questions or want to send any corrections, send them
wherever you can. I also have an e-mail you can
send it there too. But spiny dogfish eat a variety
of invertebrates including shrimp, fish, crabs, jellyfish,
squid, and sea cucumber. Unless it's super old and
chilling in vinegar. Then it's a sea pickle.
Yeah, we're going to just end the entire podcast after that
joke. That was bad.
That's just curtains on the entire thing.
I'm just kidding. Y'all are stuck with me.
So Spidey dogfish are ovoviviparous.
So that means the eggs hatch internally, but baby continues
to develop until it's ready to be birthed into a little shark
pup. Now, unlike every other animal,
this rather small shark has an insanely long gestation period,
typically lasting about 18 to 24 months.
And for reference, the typical rule is the larger the animal,
the longer the gestation period or the time that it takes to
make the baby. So elephants usually take a
while, about two years, while mice usually it takes about a
month. So spiny dogfish can give birth
to about 5 to 6 pups usually, but the numbers can vary.
They are listed as vulnerable under conservation status as
their numbers do well across most oceans, but they have had
some decline, especially in Europe where they were fished
into critical endangerment. But thankfully there are groups
such as Greenpeace that come together to help advocate for
sharks and a given the spiny dogfish in particular a chance
to rebound, which their numbers have been doing pretty well.
Now that is exactly what I have for these spiny dogfish and for
this episode. So I appreciate you guys
listening. I am going to try to get this a
little bit more routine. I appreciate y'all being here,
hanging out, chatting, just kind of interacting in general.
It's been a lot of fun comment DM your favorite shark fact.
I might just share it Some of my favorites at the beginning of
the episode. Give us a five star rating or
tell me what you want me to see do different.
Anything like that. I appreciate y'all being here.
Be kind to each other and I will see you guys in the next one.