Doctor Who: Sea Devils, Silurians, Madame Vastra Explained

The creatures of Doctor Who: Legend of the Sea Devils have a complicated family tree which creates no shortage of continuity head-scratchers

Doctor Who Legend Of The Sea Devils
Photo: BBC

The next Doctor Who special is rapidly approaching – the penultimate adventure of Jodie Whittaker’s Doctor, who proved that not only do a lot of planets have a North, at least a couple also have a Yorkshire.

To mark this adventure, the Doctor is facing off against one of her few headlining alien nemeses that haven’t been given another go-round since the new series started in 2005 (We may have to find a name other than “new” for that soon). Yes, the Doctor is dealing with the Sea Devils, on a pirate ship, alongside the legendary pirate Zheng Yi Sao, inching the series ever closer to the Doctor Who/Our Flag Means Death crossover the people are crying out for.

Now, this is Doctor Who, so we can be pretty sure that any necessary background exposition will be delivered by the Doctor as soon as a Sea Devil shows up on screen. That said, a bit of background reading and viewing will still help, as Sea Devils and their cousins the Silurians have one of the most complicated histories of any Doctor Who monster that doesn’t involve actual parallel universes.

But to fully understand it, we need to go back. Way back.

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The Age of Homo Reptilia

The Doctor’s two biggest bads, the Daleks and the Cybermen, each represent possible futures for humanity. The Daleks are basically humans that are consumed by racism to the point they just want to sit in a jar and drive around an angry tank. Cybermen are humans who have replaced all the meaty bits with technology until there’s no actual human left.

But while Sea Devils and Silurians have never looked remotely human, unlike Daleks and (most) Cybermen, they aren’t alien either.

The idea is that before humans evolved, reptiles evolved sentient, bipedal humanoids who built their own technologically advanced civilisation. Now at surface level, this is one of those ridiculous premises you just sort of have to swallow if you’re a Doctor Who fan, like the Earth spontaneously growing a forest overnight to ward off solar flares, or a robot made out of sweets, but it’s not as far out as it sounds.

Recently researchers at Cambridge University did a study (called, aptly, “The Silurian Hypothesis”) that asked how much evidence such a civilisation would leave for palaeontologists, and the answer is “It’d probably be indistinguishable from a volcanic super-eruption or natural climate change”.

Doctor Who Legend of the Sea Devils

When this happened in Doctor Who history is a question only somewhat less confused than “When were all the Jon Pertwee stories with UNIT set?” The first homo reptilians the Doctor encounters are called “Silurians”, after the Silurian period, placing them between 443.8 million years ago and 419.2 million years ago, and their first story features a globe that shows Earth to have only one continent, placing it at least 200 million years ago.

However, in the Sea Devils’ first story, the Doctor suggests that Eocenes would be a more accurate name, dating them roughly 55 million to 35 million years ago. This places them after the extinction of the dinosaurs (which they were supposed to co-exist with them) and before the “primitive apes” they talk about, which would eventually become humans. This theory we can probably put down to ‘A lot of the time the Doctor doesn’t know what they’re talking about’.

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In The Hungry Earth, the Doctor says the civilisation existed 300 million years ago, which would have placed them about 50 million years before the dinosaurs.

The one thing that is established about this civilisation is how it ended – an enormous object, almost a quarter of the size of the Earth itself, was headed for a collision course with the planet, and so everyone put themselves in suspended animation in underground (or underwater) bunkers.

This object would turn out to be the planetoid that would become Earth’s moon. Which turns out to be a giant egg. Now that premise might sound ridiculous but… actually, yes, yes that is just bunkum.

But while this marks the end of the civilisation that birthed the Sea Devils, it is only the beginning of the story.

The “Silurians”

The Silurians first appeared in the Jon Pertwee era story, ‘Doctor Who and the Silurians’, which takes its name from the reptilian humanoids, and the true, canonical and established real name of the show’s protagonist.

The name of this people came from the notes of a dead scientist the Doctor finds.

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The Silurians are woken from their hundred million year ice-nap by humans carelessly building a nuclear power plant on top of their home. In appearance, they were reminiscent of The Creature from the Black Lagoon, and they had a third eye on top of their heads. They speak in a Type 3 70s Alien Voice – sounding like they’re talking from inside a fish tank.

Doctor Who Silurians

Initially, the Silurians are a threat to humanity, but the Doctor tries to broach a peaceful solution, until the Brigadier genocides them all.

This species of Silurian is seen only once more in the TV series, when it teams up with the Sea Devils in the Fifth Doctor story ‘Warriors of the Deep’, where both species represent a threat to humanity, but the Doctor tries to broach a peaceful solution, which doesn’t work out, and eventually, he is forced to genocide them all.

The Sea Devils

This brings us neatly to the Sea Devils. Jon Pertwee’s Doctor runs into them not long after the Silurians. They don’t look much like the Silurians, with an appearance that is part turtle, part Plesiosaur, part Mon Calamari. When we first see them they’re dressed largely in oversized string vests (I guess someone thought that since they live in the sea they should wear fishing nets?), are armed with killer torches, and speak in the Type 2 70s Alien Voice – menacing whispering. You might think it would make more sense for these to be the homo reptilia that sound like they’re speaking from underwater, but no.

The name “Sea Devils” comes from the ranting of a distressed sailor, but it’s quickly adopted as canon.

The Master lures the Sea Devils into attacking the humans as part of a byzantine and overcomplicated plan to take revenge on the Doctor, but the Doctor attempts to negotiate a peaceful solution. It goes wrong, so the Doctor has to reverse the neutron flow on the Sea Devils’ superweapon, and genocide them all.

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Doctor Who Legend of the Sea Devils Craig Els

When we see them again, in their crossover with the Silurians in ‘Warriors of the Deep’, they have ditched the string vests in favour of Samurai outfits for some reason. Judging by the setting and publicity shots of ‘Legend of the Sea Devils’, it seems they’re going to lean into that in a way that I’m sure won’t end up being problematic.

‘Warriors of the Deep’ is the last we see of either reptile species, but it turns out there are still more genetic offshoots to come.

Homo Reptilia

When Matt Smith comes across the Silurians for the first time in ‘The Hungry Earth’ we discover this species is another “gene stock” entirely. No turtle faces, no third eye, these homo reptilia are just straight up lizard people, with make-up straight out of a Star Trek: The Next Generation diplomatic conference (apart from the extras who always wear masks that require much less make-up).

This species turns up a few times through the new series, beyond their initial adventure. They appear at the Battle of Demon’s Run when the Doctor calls in his favours. They are part of the “Alliance” that traps the Doctor in the Pandorica (although it remains to be seen if these were second-century homo reptilia who woke up early, or future homo reptilia who nipped back in time to incarcerate him).

We also learn that not all Silurians buried themselves underground. In ‘Dinosaurs on a Spaceship’, we discover there was a Silurian ark, crewed by this species and filled with species of dinosaur, until they were all spaced by a villain who looked eerily like the First Doctor.

How do you solve a problem like Madame Vastra?

This species also grants the Silurians their first recurring character, but with that comes a bit of a continuity headache.

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Doctor Who Madame Vastra

Off-screen, at some point, the Doctor runs into another Silurian colony, this time one that has been unearthed by the construction of the London underground. For once there’s no need for genocide, and the Doctor convinces the Silurian he encounters to become a Victorian Lady Detective.

But when does this happen? Vastra makes it clear that she is an old friend of the Doctor, no stranger to oddities like regeneration. But the Doctor only encounters her species for the first time in ‘The Hungry Earth’. It’s possible that the Doctor snuck off to have an offscreen adventure while Amy and Rory were napping, but it’s implied that their friendship goes back much further than that. Big Finish will probably clear that up at some point.

The Future Silurian Civilisation

This variety of Silurians is also notable for being the one that doesn’t get tragically genocided despite the Doctor’s best efforts. Instead, the Silurians go back into cryosleep, while the Doctor gives a kid the job of informing the entire human race that in a few centuries they need to make room for an entire new intelligent species climbing out of the Earth looking to peacefully co-exist.

The thing is, the Doctor told them to go to sleep for “a thousand years”, which will have them waking up in approximately 3020 AD. Unfortunately, multiple sources (‘The Beast Below’ and ‘The Ark in Space’ among them) indicate that the entire planet is rendered unhabitable by solar flares two centuries previously, causing the entire human population to flee into space.

This may be a very clever ruse by the Doctor to avoid another inter-species war. The reptiles will probably be fine with the excess heat and radiation. But given everything the Doctor’s said about dating when the Silurian civilisation was in the first place, he probably just did it by accident. For a time traveller, he’s not great with dates.

Homo Reptilia in Space

But are the Earth-bound homo reptilia the only homo reptilia in our solar system? We already know that Earth has a precise twin in the form of Mondas, with identical humans (originally) and identical continents, so is it possible it also has its own Silurians and Sea Devils? While we’re at it, Mars has its own reptilian humanoids in the form of the Ice Warriors. The descendants of homo reptilian colonists from Mondas or Earth perhaps?

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It’s also worth noting that, bar some minor scuffles with humanity, none of these species have ever gone on a full genocidal rampage to match that of the monkey-descendant Cybermen, Daleks or Toclafane. Maybe the Doctor backed the wrong horse(-like dinosaur) after all?

Doctor Who: The Legend of the Sea Devils airs on Sunday the 17th of April at 7.10pm on BBC One.