"Blind species" refers to animals that have lost their eyesight through evolution, often due to living in dark environments like caves or deep ocean waters. These species have adapted to their surroundings by developing other senses, such as touch or smell, to navigate and find food. Examples include certain types of cave fish and blind salamanders. The absence of sight in these species is not a disadvantage; instead, it allows them to thrive in their specific habitats. Their bodies may also exhibit other adaptations, such as enhanced sensory organs or unique coloration, which help them survive in the absence of light.