The Lactrans are a sapient non-humanoid species native to the planet Lactra VII. They resemble 30 meter-long slugs with a long tentacular appendage on the snout used for manipulating objects. Silent creatures, they communicate solely by telepathy, and their intellect is extremely advanced. Lactran infants often find humanoid creatures to be scary, while Lactran females regard humanoids as horrendously ugly.
In 2270, the USS Enterprise visited the planet on a mission to investigate the disappearance of the USS Ariel. Captain James T. Kirk and his crew soon discovered that the Lactrans had placed the Ariel crew into a type of zoo which house different types of animals.