Animal Classification

The main ranks, from broadest to narrowest, are kingdom, phylum, class, order, family, genus and species. Animals sit in the kingdom Animalia; most animals with a backbone are in the phylum Chordata. This page browses the three middle ranks — class, order and family — because those are the levels where useful groupings appear.

An order is a broader group than a family. Carnivora is an order containing dogs, cats, bears, seals and weasels; within it, Felidae is the cat family and Canidae the dog family. Order groups animals sharing a deep common ancestor; family narrows that to a closer relationship.

Common names describe appearance or habits, not ancestry. Red pandas and giant pandas share a name but belong to different families entirely. Killer whales are dolphins. Honey badgers are weasels, not badgers. Classification tracks evolutionary relationship, which frequently contradicts everyday naming.

It is the two-part scientific naming system giving each species a genus and species name in italics — Panthera leo for the lion. It provides one unambiguous name worldwide, unlike common names, which vary by language and region and are often reused for unrelated animals.

Frequently. Genetic evidence regularly reveals that groups defined by appearance are not natural evolutionary units, so species are moved, split or merged. Whales being placed among the even-toed ungulates, alongside hippos, is a well-known example.