Vertebrates, which form a subcategory of animals, are distinguished by their backbone, or spine. This central component of the body has allowed for great evolutionary success and therefore there are an immense variety of vertebrate species. From human beings to fish, snakes and sloths, vertebrate animals come in a wide array of shapes and sizes. But what makes vertebrates special? The structure of their body is the obvious first difference from other animals. The spine supports the internal organs along with external limbs and allows for greater levels of coordination and control. The double-ended nervous system and four-chambered heart provide sufficient energy and mobility. Vertebrates additionally have complex and adaptive immune systems, which protect them from disease. These features also support advanced cognitive processes, such as the capacity for wordless communication among some species, as well as voluntary actions in higher-order functioning beings like humans. At the same time, vertebrates possess a variety of other special adaptations. Many species capable of flight, such as birds and bats, are vertebrates. Others, such as dolphins and whales, can navigate and live underwater using specialized sensory systems as well as anatomical adaptations. This adaptive ability enables species to occupy different geographic areas and exploit a wider range of resources. All of these features have enabled vertebrates to become one of the most abundant and successful classes of animals, with new species continually being discovered. To conclude, the commonality shared among vertebrates is the backbone, which has enabled various species to thrive in a large number of habitats. With adaptations such as a four-chambered heart, adapted immune systems, and cognitive abilities, vertebrates have been able to reach levels of success and diversity unmatched by any other animal group. This is what makes them truly special.