The Furlings possess advanced technology, including an archway device that instantaneously transports users over great distances. When SG-1 discovered the technology on an uninhabited planet, Colonel Jack O'Neill and Harold Maybourne were transported to the planet's nearby moon. There Maybourne hoped to find a secret paradise, but instead found a empty land strewn with the remains of its long-dead colonies. If these men and women were Furlings, they were quite humanoid.
HOMEWORLD - Unknown
FIRST APPEARED - N/A
BEHIND THE SCENES
The "Furlings" made an appearance (of a sort) in the 200th episode of Stargate SG-1, though this Ewok-like appearance should not be taken as canon. It includes various stories and fantasies imagined by SG-1 which are likely not based in reality.
Robert C. Cooper invented the name "Furlings" in SG-1's second season because he believed "the fifth race" sounded much better for an episode title than "The Fourth Race."
The Torment of Tantalus - SG-1 learns about the ancient alliance to which the Furlings belonged when they visit the planet where the alliance once met.
The Fifth Race - The Asgard tell O'Neill about the ancient alliance, which included the Furlings.
Paradise Lost - Maybourne leads the team to a world where they find Furling technology: a transporter that sends O'Neill and Maybourne to an extinct colony on a nearby moon.
200 - SG-1 reads a movie script loosely based on their adventures, including a meeting with the Furlings that never happened ... and which resulted in the destruction of their planet.