A nature documentary or wildlife documentary is a genre of documentary film or series about animals, plants, or other non-human living creatures, usually concentrating on video taken in their natural habitat but also often including footage of trained and captive animals. Sometimes they are about wildlife or ecosystems in relationship to human beings. Such programs are most frequently made for television, particularly for public broadcasting channels, but some are also made for the cinema medium. The proliferation of this genre occurred almost simultaneously alongside the production of similar television series.