Race moved underground and grew dependent upon the "Caretaker" alien who had accidentally made their planet's atmosphere incapable of producing a water cycle some 500 generations ago. The average Ocampan life-span is nine-years.

Unaware of the aliens as anything but a benevolent god, their ancient texts record the disaster as "the warming" when the benevolent Caretaker opened an underground chasm to allow them to build a city there. They have let their telepathic and other abilities atrophy but care until death for those "honored guests" rejected and infected by the medical testing their Caretaker completes in his search for a mate. In fact, such guests are stared at by the natives for the contact they have had, and believe they are "immune" from their fatal disease. Some less-latent outcasts are tolerated and have a farm colony outside the city. Some have found fissures to the surface, but are closed up for protection against the intrusive Kazon-Ogla above. The mainstream Ocampa hold the ancient stories of cognitive abilities as apocryphal.

Ten months after being drawn to the Delta quadrant, the U.S.S. Voyager found Ocampa on the Array of another Nacene entity and the Caretaker's mate, Suspiria. The stories of the Nacene proved to be true. Through her guidance, these Ocampa had developed telekinetic and telepathic abilities, and had extended their lifespan to over 20 years.