Crocodiles are ancient reptiles that have coexisted with humans in Australia for thousands of years. These formidable predators are widely distributed across the vast tropical north of the continent.
Australia’s Crocodile Species
Australia is home to two distinct species of crocodiles: the Saltwater Crocodile (Crocodylus porosus) and the Freshwater Crocodile (Crocodylus johnstoni). These species exhibit notable differences in characteristics and preferred habitats. Saltwater crocodiles are generally larger and more robust, while freshwater crocodiles are smaller and possess a more slender snout. Their habitat preferences also differ, with one favoring coastal and estuarine environments and the other primarily found in inland freshwater systems.
Saltwater Crocodile Range
Saltwater crocodiles, often referred to as “salties,” are the largest living reptiles, found extensively across northern Australia. Their range extends from the west coast of Western Australia, across the Northern Territory coastline, and south to Gladstone or Rockhampton in Queensland, encompassing coastal regions, estuaries, tidal rivers, and mangrove forests. These adaptable reptiles can tolerate a broad range of water salinities, from pure freshwater to full-strength seawater, and have even been recorded in water twice as saline as the ocean. While known for their presence in brackish and marine environments, saltwater crocodiles also inhabit freshwater billabongs and swamps far inland, particularly during the wet season. Notable areas with thriving saltwater crocodile populations include the river systems near Darwin, such as the Adelaide, Mary, and Daly Rivers, as well as the Kimberley coastline in Western Australia.
Freshwater Crocodile Range
Freshwater crocodiles, commonly known as “freshies,” are endemic to northern Australia. Their distribution largely overlaps with saltwater crocodiles across Western Australia, Queensland, and the Northern Territory. However, freshies are predominantly confined to inland freshwater systems, inhabiting rivers, creeks, billabongs (isolated waterholes), and swamps.
They can be found in areas where saltwater crocodiles cannot, including more arid and rocky conditions such as Katherine Gorge in the Northern Territory. Although they can tolerate some saltwater, freshies are typically found upstream from tidal influences, as larger saltwater crocodiles tend to restrict their presence in more saline areas. Freshies are generally smaller than salties, with most adults reaching about 3 meters in length, and are not considered dangerous to humans unless provoked. Populations exist in permanent freshwater bodies, including the Lake Argyle and Lake Kununurra regions in Western Australia, which host some of the largest known populations.