Terrestrial animal Terrestrial animal The term terrestrial is typically applied for species that live primarily on the ground, in contrast to arboreal species, which live primarily in trees. There are other less common terms that apply to specific groups of terrestrial animals: Terrestrial invasion is one of the most important events in the history of life. Terrestrial lineages evolved in several animal phyla, among which vertebrates, arthropods, and mollusks are representatives of more successful groups of terrestrial animals. Terrestrial animals do not form a unified clade; rather, they share only the fact that they live on land. The transition from an aquatic
Blindness in animals Blindness in animals Visual perception animals play an important role in the animal kingdom, most importantly for the identification of food sources and avoidance of predators. For this reason, blindness in animals is a unique topic of study. In general, nocturnal or subterranean animals have less interest in the visual world, and depend on other sensory modalities. Visual capacity is a continuum, with humans falling somewhere in the center. Animals that live only in caves, called troglobites (meaning 'cave dwellers'), are adapted to life in the dark. Many such species are blind or have poor vision. Blindness at birth serves