An alligator is a vertebrate. Vertebrates are animals that possess a backbone or spinal column, which is a key characteristic of this group. Alligators, along with other reptiles, birds, amphibians, fish, and mammals, are classified as vertebrates due to their skeletal structure, which includes a bony or cartilaginous spine.
In contrast, invertebrates are animals that lack a backbone, such as insects, crustaceans, and mollusks. Alligators belong to the class Reptilia and are part of the order Crocodylia, which highlights their evolutionary relationship with other vertebrates. Their well-developed skeletal system allows them to support their body weight and provides protection for their internal organs, essential for their survival in diverse aquatic and terrestrial habitats.