Sontarans come from a large, dense planet named Sontar in the "southern spiral arm of the galaxy" which has a very strong gravitational field, which explains their compact stocky form.

The Sontarans have an extremely militaristic culture which prizes discipline and honour as its highest virtues; every aspect of their draconian society is geared toward warfare, and every experience is viewed in terms of its martial relevance.

According to their creator Robert Holmes, Sontarans do have a highly developed artistic culture, but have put it on hold for the duration of the war, while the opening chapter of the novelisation of The Time Warrior, based on Holmes' incomplete draft, refers to Linx listening to the Sontaran anthem while his spaceship is in flight.

The Sontarans depicted in the series have detached, smug personalities, and a highly developed sense of honour; on multiple occasions, the Doctor has used his knowledge of their pride in their species to manipulate them.

In Earthlike atmospheres, the Sontaran armour suit requires a change of gases every 27 hours, also conducted through the probic vent.

In the episode "The Poison Sky", it is revealed that the Sontaran Empire have been at war with the Rutan Host for more than 50,000 years,[5] and which, at a time around 2008, they are losing.

[8] The Sontarans are a monogender-asexual (a "male gender-only" species); they reproduce by means of cloning rather than sexual reproduction, and thus for the most part are extremely similar in appearance.

In The Time Warrior, Linx states that "at the Sontaran Military Academy we have hatchings of a million cadets at each muster parade."

General Staal comments that "words are the weapons of womenfolk"[8] and that the clone of Martha Jones performed well "for a female"[3] as commentary on the gender inequalities of other species.

As multiple genders are foreign to them, Sontarans are known to confuse the human male and female sexes; Strax routinely addresses young women as "Boy"[10] and vice versa,[11] and claims not to have known that River Song was a woman.

When first used by Commander Linx in The Time Warrior, it shows the ability to fire a beam which can disarm by knocking the weapon out of the wielder's hand, hypnotise, as well as cutting through wood, disabling limbs and killing.

The Invasion of Time saw Commander Stor using the small rod again, but also in episode six, a Sontaran trooper uses a short black rifle-like laser to try to burn through a lock on a door inside the TARDIS.

Commander Kaagh, a surviving pilot from the Tenth Sontaran Battle Fleet, had slightly different armour due to being from the special forces.

During rehearsals for their first appearance, Kevin Lindsay, who portrayed the original Sontaran, Linx, pronounced the race's name as "son-TAR-an."

The Sontarans made their first appearance in 1973 in the serial The Time Warrior by Robert Holmes, where Linx is stranded in the Middle Ages.

In "Turn Left" (2008), the same events are depicted in a parallel universe, where Rose Tyler (Billie Piper) describes their plan as foiled by Torchwood (characters from the spin-off show of that name), at the cost of their lives, with Torchwood leader Captain Jack Harkness (John Barrowman) being captured by the Sontarans.

A lone survivor from the events of "The Poison Sky", Commander Kaagh (Anthony O'Donnell), next appears in The Last Sontaran (2008), from spin-off series The Sarah Jane Adventures.

Series 6 episode "A Good Man Goes to War" (2011) introduces Commander Strax (Starkey), a Sontaran nurse who has been assigned this role as a means of making penance.

He fights on the side of the Doctor and his allies, which include the Silurian warrior Madame Vastra (Neve McIntosh) and her wife, Jenny Flint (Catrin Stewart).

Strax then appears alongside Vastra and Jenny in "The Snowmen" (2012), "The Crimson Horror", "The Name of the Doctor" (both 2013), and "Deep Breath" (2014).

First appearing in the season premiere, 'Chapter 1: The Halloween Apocalypse', the Sontarans plan to exploit the Flux crisis to take over Earth in its various time periods.

They sent a group back in time to Crimean War-era Sevastopol in 'Chapter 2: The War of the Sontarans' as a trial run, only to be defeated by the Doctor while Dan and Karvanista take out the main fleet.

The Doctor Who role-playing game published by FASA claimed that they were all descended from the genetic stock of General Sontar (or Sontaris), who used newly developed bioengineering techniques to clone millions of duplicates of himself and annihilated the non-clone population.

A Sixth Doctor Lost Story from the mid-1980s, written by Andrew Smith,[note 2] it features the Sontarans and the Rutans on nineteenth century Earth, tracking down a scientist named Jacob, who escaped through time and space.

The audio ends with the Doctor and Peri helping Jacob and his wife fake their deaths so that they can go into hiding on a primitive, isolated planet to get away from their need for revenge on the Sontarans.

They have also appeared in several spin-off novels, including Lords of the Storm by David A. McIntee, where the Fifth Doctor and Turlough have to stop a Sontaran scheme to take control of a colony world where Tzun technology has been hidden.

The novel Warmonger sees the Sontarans join an alliance of alien races assembled by the Fifth Doctor to defeat the mercenary army of renegade Time Lord Morbius, although the Sontarans are unaware that they follow the Doctor as he adopts the alias of 'Supreme Coordinator', which is shortened to 'Supremo' by his Ogron bodyguards.

In The Outsider (DWM #25-26), by Steve Moore and David Lloyd, a Sontaran named Skrant invaded the world of Brahtilis with the unwitting help of Demimon, a local astrologer.

In Steven Moffat's short story "What I Did on My Christmas Holidays by Sally Sparrow" (the basis for the Tenth Doctor episode "Blink"), the Ninth Doctor has a rooftop sword fight with two Sontarans in 21st century Istanbul, defeating them with the help of spy Sally Sparrow, apparently before the events of "Rose" in his personal timeline.

The Sontarans also feature in the Kroton solo strip Unnatural Born Killers (DWM #277) and the Tenth Doctor's comic strip debut The Betrothal of Sontar (DWM #365-#368), by John Tomlinson and Nick Abadzis, where a Sontaran mining rig on the ice planet Serac comes under attack by a mysterious force.