Animals are multicellular eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million in total. Animals range in size from 8.5 millionths of a metre to 33.6 m long and have complex interactions with each other and their environments, forming intricate food webs. The study of animals is called zoology. Animals may be listed or indexed by many criteria, including taxonomy, status as endangered species, their geographical location, and their portrayal and/or naming in human culture.

By common name

By aspect

By domestication

By eating behaviour

By endangered status

By extinction

List of extinct animals

By region

By individual (real or fictional)

Real

Fictional

By taxonomical classification

Phyla

The animal Kingdom contains some 35 extant phyla. Basal animals are delineated according to the following cladogram: Animals: Porifera, Diploblasts Diploblasts: Ctenophora, ParaHoxozoa ParaHoxozoa: Placozoa, Cnidaria, Bilateria/Triploblast Bilateria: Xenacoelomorpha, Nephrozoa Nephrozoa: Protostomes, Deuterostomes

Deuterostomia

Protostomia

Ecdysozoa

Spiralia

Chordata

Fish

Amphibians

Reptiles