The term "higher animal" refers to animals with more complex nervous systems and advanced physical structures that differentiate them from invertebrates. Synonyms for higher animal include vertebrates, which are animals with backbones such as mammals, birds, fish, reptiles, and amphibians. Another synonym is megafauna, which refers to large animals such as elephants, lions, and whales. Some may also refer to higher animals as intelligent animals, which includes primates like chimpanzees and bonobos, dolphins, and certain bird species. Ultimately, what distinguishes higher animals from others is their advanced cognitive abilities, social structures, and physical capabilities.