Two species of crocodile live in Kakadu: the Freshwater Crocodile ("Crocodylus johnstonii") and the Estuarine, or Saltwater Crocodile ("C. porosus"). Freshwater Crocodiles have a narrow snout and a single row of four large boney lumps called ‘scutes’ immediately behind the head. Estuarine Crocodiles do not have these scutes and their snout is broader. The maximum size for a ‘freshie’ is 3 metres, whereas a ‘saltie’ can exceed 6 metres.