Kalmar “genus” tana nufin matsayi na haraji da aka yi amfani da shi wajen tantance halittu masu rai. Anas jinsin tsuntsayen ruwa ne, wanda ya hada da nau'in da aka fi sani da agwagi, kosai, da mallards. Don haka, kalmar “Genus Anas” tana nufin musamman ga sunan kimiyya na rukunin tsuntsaye da aka fi sani da agwagi, koraye, da mallards.
