Intro to Zoology/Vertebrate Zoology
Vertebrate zoology is the study of animals that have a spinal column or backbone.
Only 3% of all animal species are vertebrates, but there is a strong history of research bias toward vertebrates. There are probably several reasons for this. Among these, is the fact that many vertebrate species are large (domestic cat sized or larger, though the majority are smaller). Also the group includes ourselves as humans, so that when people think of animals, they tend to think of vertebrates.
Vertebrates are all characterized by a segmented spinal column and a distinct differentiated head. These animals possess internal skeletons which include the vertebral column which at least partially encloses the spinal cord and a skull which houses the brain. Though we tend to think of vertebrates having limbs (like us), most (the fishes) do not have external limbs.
Animals in this category includes those in the subphylum Vertebrata: fish (over 30,000 living species), amphibians (about 7,300 living species), reptiles (about 8,700 living species), birds (about 10,000 living species), and mammals (our own group, with about 5,000 living species.