Top Ten Sharks #9 – The Blue Shark, Prionace glauca

I mean…How is it not cute? The derpy mouth, the big, cartoon eyes, that snoot ripe for booping! This is the shark you want to hug! Anyone who doesn’t think sharks are cute is not paying enough attention to these darlings! (Credit: Mark Conlin/NMFS – Public Domain)

Why am I following up the behemoth with a mouth that could crush the core of the Earth, the megalodon, with a 3m (around 10 feet) cuddly toy?

Well because I think sharks are cute. I think the blue shark is one of the cutest animals on the planet. I think it’s absolutely gorgeous and a fine example of the prettiness of sharkhood.

Right now I have a poll going on twitter and around two-thirds of people think sharks are not cute. The thing is, some of them just are. I mean, I am sure there will be some monsters on this list, sharks are nothing if not diverse. But they can be cute, too!

I think people hear ‘shark’ and they don’t think of something like the blue shark, a slender, sleek, teddy bear of a shark. With a cute little overbite, and those big, cartoon eyes. They think of great white sharks breaching the water, protruding their jaws to snatch at some food. They think of monsters tearing flesh from body. Maybe they think of the goblin shark and it’s weird thrustable jaw, or the huge gaping chasm of the basking shark’s mouth.

The overwhelming diversity of ‘sharks’ – All of these things are ‘sharks’ – some are weird, some are gorgeous, some are cute, some are monstrous. I happen to find the great white absolutely adorable but I can accept some people’s mileage may vary with that one. (Credit: LittleJerry CC-BY-SA 4.0)

Those three sharks I mentioned right there? Not even in the same families – The great white is in the Lamnidae, the goblin shark in the Mitsukurinidae and the basking shark is in the Cetorhinidae. I cannot emphasise enough how little ‘shark’ means as a classification in the face of the overwhelming diversity of sharks.

So, pardon me if you think me rude, but fuck off if you think sharks aren’t cute! The blue shark definitely is!

The blue shark is in the family Carcharhinidae – the ‘Requiem Sharks’. Yes, it does sound like an ecclesiastical gang from the 1950s.

The requiem sharks are mainly warm-water sharks, medium sized, mostly give birth to live young (some sharks lay eggs – or ‘mermaids purses’ – I recently had a conversation about these with my niece after we found some washed up on the beach…it was awesome!) and include such famous aquarium examples as the reef sharks and the tiger shark.

A ‘mermaid’s purse’ – In this case identified as a skate egg. Sharks lay similar looking structures with their young inside. (Credit: Xtylee CC-BY-3.0)
The slender, pointed form of the blue shark. You can still see that big, beautiful eye. There’s something about the shape of a blue-shark, torpedo-like, yet soft and yielding, like a nerf-dart. (Credit: Shane Anderson. Public Domain)

But none of them has that ‘cuddly’ look quite like the blue shark.

Their narrow, pin-like lower teeth give us a great indication as to their diet. Generally when it comes to aquatic animals, ‘if they’re big and wide, something large has died. If they’re short and thin there’s small fish within.’ I just made that up, but that’s basically the gist of it.

It has long, pin-like lower teeth perfect for snagging smaller fish, squid and the like. That doesn’t stop them eating bigger prey, any more than dentures will stop a human eating a toffee. If a shark wants it, a shark will usually try to get it.

Of course in case you couldn’t tell by the form – long, slender body, big fins, pointed snout – despite being relatively slow and seemingly lazy when merely swimming, the blue shark is built for power and speed in a hunt. It is why it is still one of the most popular sharks for sport fishing. A large number of businesses that do shark fishing off the UK work with a catch-tag-release scheme so usually I’d advise against sport fishing for sharks but in the case where it is to aid a conservation effort I say go for it.

Shark fishing, and tagging off the Irish coast. Can’t quite remember the presenter’s name – I think it’s Steve Leonard, a vet and television presenter. Obviously not entirely without anguish for the shark but ultimately it takes a grown man sitting on top of it to stabilise a shark, on land, so it can be tagged! They’re strong, effectively murder muscle tubes. Sharks are also resilient and whilst tagging efforts like this can be harrowing, they allow us to gather more data to better understand the sharks, their migration patterns, their behaviour and therefore how best to protect and conserve them moving forward. (Credit: BBC)

They are notoriously countershaded. We mentioned that in our introduction but if you need a reminder it’s where there is a colour difference between the top (dorsal) side and bottom (ventral) side. In this case the blue shark lives up to its name. They can be the most remarkable, deep, ocean-blue shades on top, with almost a hint of a shimmer, and nearly white underneath. The best part is the middle, where the two colours blend into an almost metallic-blue band. These sharks are otherworldly gorgeous.

Also remember when I mentioned in the introduction that some female sharks have developed thicker skin than their male counterparts to deal with some aquatic BDSM-like activities? Blue sharks are one of them. The female can have skin up to three times thicker than a male and many female blue sharks exhibit scarring – In fact it can be a quick way to tell the sex of a blue shark.

For anyone worried about the wellbeing of female sharks I wouldn’t worry too much. Sexual dimorphism (remember that? Physical or behavioural differences between sexes of the same species) exists in sharks and generally the females are larger than the males.

Besides being cute and sexually aggressive, though, what else is there?

They give birth to live young (or are viviparous) in what can be ridiculously large litters. If you thought ‘Octomom’ had a job on her hands then prepare to be amazed. Blue sharks can have litters of over 100 pups. That’s a lot of baby sharks.

Oh, no! I said it.

Sing it with me now…BABY SHARK! DO-DOO DO-DO-DOO-DOO!

I couldn’t find any good images of a baby blue shark, so have this short YouTube clip instead. Bothering and harrassment of these animals should always be minimised, except where absolutely necessary for vital research. (Credit: Shark Whisperers)

The average litter is probably somewhere in the 30s, and the thing is sharks tend to be fairly hands-off parents, so once you’re out you’re on your own! It might seem harsh but could you take care of 35 young kids all at once? (Fist-bump to all the primary school teachers out there!)

One of the other remarkable things about blue sharks is their swimming. They are epipelagic. ‘Pelagic’ refers to how deep the sea is, being divided into different pelagic zones. In this case the epipelagic zone is anywhere from the surface down to about 200-300m, basically the parts sunlight reaches. Most, at least known, ocean life lives in this zone. So they don’t swim very deep, big whoop. But they swim very, very far.

Blue sharks are considered one of the most migratory of all sharks, because they sort of just swim around in circles in the Atlantic, covering loops of nearly 10,000km each year! It’s absolutely astounding.

We often get blue sharks as visitors to UK and Irish waters, especially off the coast of Ireland, or the South West coast, where the gulf-stream – which they follow on their migrations, using their long, gorgeous fins to ‘glide’ on the currents and save energy, lazy bastards – meets the British mainland.

A remarkable map based upon tagged shark data, showing the ranges and migrations of blue sharks. The red lines represent the movements of females, the blue lines represent the movement of males. You can see what far ranging travellers they are. One interesting thing to note is the contrast in East-West movement in female and North-South movement in males. Blue sharks tend to travel in same-sex groups, so could there be some advantage to this ‘splitting up’ and then coming togther in the mid-Atlantic to breed? (Credit: © 2014 Vandeperre et al. CC-BY-4.0)

Unfortunately this wide-range and breeding prowess makes them a strangely threatened species. Numbers have been on the decline and one of the biggest problems is blue sharks getting caught in large-scale fishing equipment and caught as by-catch (the stuff you’re not fishing for). A terrible waste of a beautiful shark and something the conservation and fishing communities need to get together and solve.

They also don’t keep well in captivity, so you’re unlikely to see one in an aquarium. Usually they last under a year in captive conditions, mostly due to competition from other sharks in their enclosures but also because enclosing a long-distance traveller like a blue shark is like sticking a marathon runner in a box. They have a habit of bumping into glass walls and tank-sides while swimming, causing injury and potential risk of infection. I mean, look at it, it’s not supposed to be captive. It swims 5,000 miles a year!

As far as natural predators goes they are likely on the menu for larger sharks, as well as predatory whales like Orca, but as ever, humans are the biggest threat. They are classified as ‘near threatened’ by the IUCN.

BOOP THE CUTE SNOOT! – (Credit: MA MarineFisheries, Public Domain)

So, that’s the blue shark. In case you thought this was just an aesthetic decision, in case you think my weird desire to hug a blue shark in some way influenced me to put it on this list, what you are looking at is a nomadic, baby-making, killing machine with a colour so captivating to look at its skin is like gazing into the ocean itself.

It’s an absolutely incredible creature and, yes, a good argument against people who think sharks can’t be cute. The blue shark absolutely is.  

Want to dive deeper into some aquatic shark content?
Our Introduction will give you the basics of shark biology, ecology and natural history.
#10 – The massive, magnificent megalodon – a prehistoric giant!

#8 – Known for it’s spiral of jagged teeth, Helicoprion – the Buzzsaw shark!
#7 – The frilled shark, a mysterious living fossil with much to tell us about sharks past.
#6 – The Great White, Apex predator, whale scavenger, more intelligent than we thought.
#5 – The Megamouth Shark – One that tells us more about what we don’t know!
#4 – The Graceful Hammerhead family – Much overfished, and is one a veggie?
#3 – The aparently philosophical basking shark! – Happy just existing.
#2 – The longest living vetebrate on earth – The Greenland Shark


Published by Karl Anthony Mercer

Karl Anthony Mercer is a writer, poet, author, musician and part-time dandy. He can often be found squatting in fields looking at insects (he is an unapologetic wasp fanatic), wandering around museums over-dressed, or hiding in a dank corner singing sad songs on a small guitar. His writing on WordPress consists of MercersPoems - an outlet for his poetry often using natural imagery, gothicism and decadence to explore the struggles of living as an autistic person; and We Lack Discipline - Where he writes about factual, often academic topics he has learned and is interested in (e.g. biology, psychology, Roman history etc.) with an inimitable, often light-hearted and irreverant style. You can support Karl by; Subscribing to the We Lack Discipline Patreon - Or buying him a coffee (he loves coffee!) -

10 thoughts on “Top Ten Sharks #9 – The Blue Shark, Prionace glauca

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: