The Silurians and Sea Devils are two fictional related ancient species created by Malcolm Hulke for the British science fiction television series Doctor Who. The Silurians are a race of scientifically advanced reptilian humanoids from the dawn of man which first appeared in Doctor Who in Hulke's 1970 serial Doctor Who and the Silurians. The Sea Devils are similar to the Silurians, but hail from the oceans and are aquatic, having debuted in the serial The Sea Devils (1972). Both species then reappeared in the 1984 serial Warriors of the Deep, which was the final appearance of both races prior to the show's cancellation in 1989. Following the show's revival in 2005, heavily redesigned Silurians were reintroduced to the series in 2010, and have recurred frequently since then. The Sea Devils were reintroduced with their designs mostly unchanged in 2022, and played a major role in the 2025 spin-off series The War Between the Land and the Sea.
Working under producer Terrance Dicks, Hulke came up with the idea of the Silurians to accommodate the show's need for more imaginative science fiction storylines during a period when its title character, the Doctor, was confined to present-day Earth. The Sea Devils were made out of a desire to bring the Silurian concept back. The further re-appearance of the pair in Warriors of the Deep was done out of a desire to bring back more antagonists following the series' twentieth anniversary. The species' redesign and re-appearance in the revived era was done to bring out the humanity in the species and allow the actors' performances to shine through, with a desire to update the Silurians to modern-day standards and expand on the concepts introduced in their original serials. Conversely, the Sea Devils' return did its best to stay as loyal to the original design of the creatures as possible.
The Silurians and Sea Devils' concept has been highlighted, though they were considered largely forgotten monsters until the Silurians' return in the revived era. In 2018, the notion of a pre-human intelligent reptilian or amphibious species was explored by the real-life scientists Adam Frank and Gavin Schmidt, who dubbed the concept the "Silurian hypothesis".
Appearances
Doctor Who is a long-running British science-fiction television series that began in 1963. It stars its protagonist, The Doctor, an alien who travels through time and space in a ship known as the TARDIS, as well as their travelling companions. When the Doctor dies, they can undergo a process known as "regeneration", completely changing the Doctor's appearance and personality. Throughout their travels, the Doctor often comes into conflict with various alien species and antagonists.
The Silurians and Sea Devils are a race of reptilian humanoids from the dawn of time. The species was highly technologically advanced, and their computers detected that a planet-like object would collide with Earth. To survive, they put themselves into hibernation, but as the planet-like object, the Moon, never crashed into the Earth, the Silurians' computers never awoke them, leaving them trapped in hibernation.
In The Sea Devils (1972), the Sea Devils, an amphibious variety of Silurians, are awakened from their hibernation by a renegade Time Lord known as the Master (Roger Delgado), who persuades them to reclaim the planet from the human race. Despite the Third Doctor's efforts to convince them otherwise, the Sea Devils eventually decide to go to war, forcing the Doctor to destroy their base. It is revealed, however, that there were many colonies still in hibernation around the world. Both species, together, in Warriors of the Deep (1984), attempt again to reclaim Earth from the humans. Set in the year 2084 during a prolonged "cold war" between factions of humanity, the pair attempt to fire an undersea base's nuclear weapons, which would cause the humans to destroy each other in retaliation for the initial strike. The Fifth Doctor (Peter Davison) attempts to make peace with them, but is unable to, forcing him to flood the base with hexachromite gas, which is lethal to Silurians and Sea Devils, to stop them. While he attempts to save the Silurians, he is unable to succeed, leaving all of them dead by the serial's end.
Revived era
Silurians are reintroduced to the series, following its cancellation and revival, in the 2010 two-part story, "The Hungry Earth" and "Cold Blood", in which Silurians are awoken in 2020 by an underground drilling operation. Having misinterpreted the drilling as a deliberate attack, the Silurians take hostages. After a protracted conflict, the Eleventh Doctor (Matt Smith) leaves behind Tony Mack (Robert Pugh) and Nasreen Chaudhry (Meera Syal) in the Silurian city to act as ambassadors to the human race when they re-awaken in a thousand years.
Following this appearance, the Silurians make various cameo appearances. Some appear in "The Pandorica Opens" (2010), as one of the species who arrived to imprison the Doctor in the Pandorica. A Silurian appears in "The Wedding of River Song" (2011) in a timeline where all of history is happening at once. A Silurian appears in a video recording in "Dinosaurs on a Spaceship" (2012), where the Silurian reveals their species sent Arks into space to search for a new planet to inhabit. All of the Silurians on board of one of these were killed prior to the episode's events by a hunter named Solomon (David Bradley) who sought to procure the ship's dinosaur cargo for himself. A Silurian appears in "Joy to the World" (2024) where one acts as a manager to a hotel that lets visitors stay in places throughout Earth's history. The Silurian is killed by the villainous Villengard Corporation.
Recurring character Madame Vastra (Neve McIntosh) is introduced in "A Good Man Goes to War" (2011) as a Silurian detective in the Victorian era, who befriended the Doctor after a brief rampage on the London Underground. She lives with her human wife Jenny Flint (Catrin Stewart), and after "A Good Man Goes To War", also employs the Sontaran Strax (Dan Starkey) as her butler, forming the trio known as the Paternoster Gang. She re-appears in several subsequent episodes alongside the pair.
The Sea Devils re-appeared in the 2022 special "Legend of the Sea Devils". In the episode, a Sea Devil named Marsissus attempts to reclaim an artefact known as the Keystone in order to flood the world, but he and his crew of Sea Devils are killed in an explosion orchestrated by the Thirteenth Doctor. A different variety of Sea Devils play a central role in the 2025 spin-off series The War Between the Land and the Sea.
Spin-off appearances
The Silurians have additionally appeared in various novels, comics, and audio dramas since their debut. Silurian merchandise depicting the original design includes busts, different kinds of figurines, and cards. Sea Devil figurines, statues, cards, and other merchandise have been produced throughout the years.
Creation and development
1970s serials
thumb|left|An original Silurian head, as used in Doctor Who and the Silurians|294x294px|alt=The head of a reptilian creature, with brown skin, a rounded mouth, and two lizard-like eyes, with a third red eye at the top of its head
Drawing on the ideas of the Quatermass serials, producer Peter Bryant and producer and script editor Derrick Sherwin decided that for the series' seventh season, the show's protagonist the Doctor should be restricted to contemporary Earth and work alongside the UNIT organisation, featured prominently in the sixth season's serial The Invasion. Producer Barry Letts and script editor Terrance Dicks, inheriting this new vision for the series, also wanted their stories for the seventh season to have a serious, deeper subtext. They approached Malcolm Hulke, co-writer of the Patrick Troughton serials The Faceless Ones (1967) and The War Games (1969), to write a serial for this new season.
Dicks requested a story that took place in caves; Hulke saw limitations with this earthbound format, as he believed there would be two types of stories, one featuring mad scientists and the other alien invasions.
The original Silurian costumes were made by visual effects designer James Ward, with the costumes being based on sketches designed by BBC Staff Director Timothy Combe. Combe suggested the idea for the species to have a third eye.
While planning stories for Doctor Whos ninth season, Dicks and Letts decided to revive the Silurian concept, being impressed with the original idea. They wanted the Silurians to originate from the sea this time. Originally dubbed "Sea Silurians", they were rechristened "Sea Devils" for dramatic effect as Hulke's storyline was edited. The Sea Devils were originally planned to be naked like the Silurians, but director Michael E. Briant was uncomfortable with the idea, leading to the Sea Devils wearing string vests in the final episode, which were leftover from another show and hastily applied to the Sea Devils. Friedlander gave each head distinctive "webbing" to set them apart from each other, with small slits in the neck being used for the actors to see out of. After re-watching the original episodes, Byrne came up with the idea of the Sea Devils being a more militaristic force for the Silurians. Moffat stated the concept of the Silurians was a "movie franchise idea", and was inspired enough by the idea to want them to return to the series. Chibnall wrote the species as if audiences were completely unfamiliar with them, believing that a mainstream audience would likely not remember the species from the last time they had appeared on-screen. Episode co-writer Ella Road stated that despite the status of the Sea Devils as returning monsters, she and the rest of the team had "loads of creative freedom" with them. The episode's titular Sea Devil, Marsissus, was portrayed by actor Craige Els, who had previously portrayed Karvanista in the series. Other Sea Devils were portrayed by various other actors.
Reception
In a review for the Radio Times, writer Mark Braxton stated that the original appearance of the Silurians, though held back by the cumbersome costumes used for the creatures, was effectively used by Hulke, with Braxton stating that "as a species they mirror our own suspicion, hatred and general insecurity." The book The Doctor's Monsters: Meanings of the Monstrous in Doctor Who similarly states that the Silurians were highly memorable antagonists as a result of the fact that the species was neither uniform nor evil, despite their physical appearance. It highlighted Warriors of the Deep for expanding on the original Silurian story by showing that, while violence was not the answer to the human and Silurian conflict, it showed via its mass deaths that violence between both sides would only lead to further violence instead of a viable solution. Susannah Lydon, writing for The Guardian, considered the Silurians to be an example of how speculative fiction engages with non-scientist audiences, highlighting their existence as part of a concept of "sleek, reptilian humanoids" existing in the Dinosaur era.
At the time of the Silurians' return to the modern series, the species had been largely forgotten by the general public, which The Guardian stated was emphasized by the lack of significant marketing or leaks regarding the species' return to the series. The design of the Silurians in the revived series was emphasized by the book Once Upon a Time Lord: The Myths and Stories of Doctor Who as symbolizing a "revitalization of the established mythology" in a respectful manner, which it felt was further emphasized by Madame Vastra, who acts as one of the series' first on-screen lesbian characters. The book New Dimensions of Doctor Who: Adventures in Space, Time and Television also analyzed the Silurians' role in this episode, analyzing how Murray Gold's musical score emphasizes the scenes featuring the Silurians.
The Sea Devils have been considered an iconic monster, with their debut serial being stated by Radio Times as having "gave British kids the shudders during their seaside holidays." In a review for Radio Times, reviewer Patrick Mulkern praised the decision to bring back the Sea Devils in "Legend of the Sea Devils", but criticized their use in the episode, believing that they didn't get any proper opportunities to be scary antagonists. Chris Allcock, in a review for Den of Geek, stated that while the use of the old Sea Devil design gave the creatures a sense of weight, the execution of the costumes had "mixed results".
In 2018, the notion of a pre-human intelligent reptilian or amphibious species was explored by the real-life scientists Adam Frank and Gavin Schmidt, who dubbed the concept the "Silurian hypothesis", named after the creatures.