The Lactrans are a civilization of thirty-meter-long slug-like lifeforms inhabiting the planet Lactra VII. Despite their appearances, they are highly intelligent and telepathic beyond Vulcan abilities.

They kept a zoo of animals on their planet, and keep intruders away by altering their sensor readings to mask their life signs.

In 2269, the crew of the USS Enterprise visited Lactra VII on a mission to investigate the disappearance of a scientific team from the USS Ariel. (TAS: "The Eye of the Beholder")