What are vertebrates?

Vertebrates are animals with a backbone and a prominent internal skeleton during development, including fishes, amphibians, reptiles, birds and mammals.

Body plan and groups

Vertebrae form the main axis along the back and a skull protects the brain. Most fishes breathe with gills in water, while birds and mammals use lungs for air. Amphibian life cycles may depend on water; the skin and amniotic eggs of reptiles facilitate life on land. Birds evolved within the reptile lineage, so everyday labels and ancestry-based classification need not draw identical boundaries. Having a backbone does not imply a single lifestyle.

Adaptation and conservation

Fins, wings and legs are examples of limbs adapted to different environments. Some species migrate; others depend on a small area. Understanding abundance requires attention to births and deaths, habitat connections, food and human impacts. Labels such as fish, bird or mammal alone say nothing about conservation status; each species and population needs assessment.