The Sixth Extinction - Broadcast and Reception

Broadcast and Reception

"The Sixth Extinction" first aired in the United States on November 7, 1999. This episode earned a Nielsen rating of 10.6, with a 16 share, meaning that roughly 10.6 percent of all television-equipped households, and 16 percent of households watching television, were tuned in to the episode. It was viewed by 17.82 million viewers and was the most watched episode of the seventh season in the United States. The episode aired in the United Kingdom and Ireland on Sky1 on May 7, 2000 and received 1.00 million viewers and was the third most watched episode that week. Fox promoted the episode with the tagline "Something is driving Mulder insane. Something he's been searching for. Something he shouldn't have found." The episode was later included on The X-Files Mythology, Volume 3 – Colonization, a DVD collection that contains episodes involved with the alien Colonist's plans to take over the earth.

Critical reception was mixed to positive. Tom Kessenich, in his book Examination: An Unauthorized Look at Seasons 6–9 of the X-Files gave the episode a positive review, noting that the episode takes the themes of "Biogenesis" and "runs with them". Den of Geek writer Nina Sordi ranked "The Sixth Extinction," along with "Biogenesis" and "The Sixth Extinction II: Amor Fati," as the fifth best episode of the series, writing, "it is evident that as progressed, the episodes surrounding those storylines and the breaking points Mulder and Scully endured push them further and further towards total, irreversible defeat. This is especially poignant when viewing this anxiety inducing trio of episodes." Monica S. Kuebler from Exclaim magazine called "The Sixth Extinction", along with "Biogenesis" and "Amor Fait", one of the "best" episodes during the show's "colonization" phase. Kenneth Silber from Space.com wrote positively of the episode, hoping that it foreshadowed answers to come, writing, "As the middle installment of a three-part story and what was then thought to be the final season premiere of The X-Files, 'The Sixth Extinction' is suffused with a somber pre-apocalyptic mood, but one vivified by the possibility that soon we'll have answers to the most important outstanding mysteries of the series."

Robert Shearman and Lars Pearson, in their book Wanting to Believe: A Critical Guide to The X-Files, Millennium & The Lone Gunmen, rated the episode three-and-a-half stars out of five. The two called the episode "the most arresting season opener in years" and noted that it "promises that maybe there's life in the old mythology yet." Shearman and Pearson, however, did critique the lack of finality to the episode, but attributed most of this to the fact that the episode was the second of a three-part mythology tale. Not all reviews were so positive. Paula Vitaris from Cinefantastique gave the episode a negative review and awarded it one-and-a-half stars out of four. She noted that "Mulder's situation is handled just poorly" and argued that Mulder's illness was created solely to provide a cross-season cliffhanger. Todd VanDerWerff of The A.V. Club awarded the episode a "C" and called it a "weird bridge". Largely, he criticized the episode for featuring "no real twists or complications here" in lieu of "things just getting worse along a linear path".