Spiders, centipedes and scorpion-like critters are among the 27 new animal species that biologists have discovered in the dark, damp caves of two Central California national parks, officials announced Tuesday.

The finds were made during a three-year study of 30 caves in Sequoia and Kings Canyon national parks.

Many of the creatures live only in caves — and some only in one particular cave of Sequoia and Kings Canyon, according to the study, conducted by park staff and biologists from Austin, Texas-based Zara Environmental.

"We thought we might find a handful of new species," said Joel Despain, cave specialist for the parks. "It was amazing to find 27."

Park officials said the cave-dwelling invertebrates can tell scientists a lot about environmental problems or changes because of their sensitivity to surroundings.

Sequoia and Kings Canyon National Parks have 238 known caves.