The Cape teal was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae.

[2] Gmelin based his description on the "Cape widgeon" that had been described in 1785 by the English ornithologist John Latham in his A General Synopsis of Birds.

[3][4] The naturalist Joseph Banks had provided Latham with a water-colour drawing of the teal by Georg Forster who had accompanied James Cook on his second voyage to the Pacific Ocean.

The Cape teal feeds on aquatic plants and small creatures (invertebrates, crustaceans and amphibians)[8] obtained by dabbling.

The Cape teal is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.