a species widespread in all zoogeographical regions

The most cosmopolitan species are known to be highly adaptable to a range of climatic and environmental conditions, though this is not always so. Killer whales (orcas) are among the most well-known cosmopolitan species on the planet, as they maintain several different resident and transient (migratory) populations in every major oceanic body on Earth, from the Arctic Circle to Antarctica and every coastal and open-water region in-between. Such a taxon (usually a species) is said to have a cosmopolitan distribution, or exhibit cosmopolitanism, as a species; another example, the rock dove (commonly referred to as a 'pigeon'), in addition to having been bred domestically for centuries, now occurs in most urban areas around the world

A number of cosmopolitan organisms have spread, these are synanthropic species. Such species are referred to as secondarily cosmopolitan. Species that are directly bred or cultivated by humans, or species that occur only temporarily in certain places (typically migratory birds), are usually not referred to as cosmopolitan.