Why do llamas have three eyelids?

Llamas have three eyelids to protect their eyes from environmental hazards such as dust, debris, and strong sunlight. The first two eyelids function like those of most mammals, while the third eyelid, or nictitating membrane, is a thin, translucent layer that can sweep across the eye to provide additional protection and moisture. This unique adaptation helps maintain their eye health in the harsh conditions of their natural habitat in the Andes mountains.