close up of head of a large australian saltwater crocodile crocodylus porosus, northern territory, australia

animal apex aquatic australia australian billabong blooded camouflage carnivore cold conceal crocodile crocodylus danger dangerous deadly ecology environment estuarine exothermic eyes habitat head headshot jaws mouth nature northern open porosus predator reflection reptile river saltwater scales scaly swamp teeth territory tropical under underwater watching water wetland wild wildlife zoology