The crocodile is the closest living descendant of the dinosaurs. A solitary animal and formidable predator, it inspires both fear and fascination. Of the different species, the marine or estuarine crocodile, Crocodylus porosus, is the largest and one of the most dangerous to humans. Present mainly in Australia, it coexists with local populations, and its impact on the ecosystem makes it a key element of coastal habitats. With an estimated population of around 200,000 individuals in the wild and 200,000 in captivity, this living fossil symbolizes power and resilience in the areas it occupies.
Article and photographs by Svetlana Markoff / Edited by Alex C.
From Saltwater to Rivers: The Varied Habitat of the Marine Crocodile
“The Salty”, as it is sometimes nicknamed, lives in warm, tropical regions. It is found in India, Southeast Asia, the Philippines, Papua New Guinea and some isolated islands like Palau and the Solomon Islands. However, due to intensive poaching, it is now endangered in many of these areas. In Australia, its territory extends from northern Queensland to the northwest of Western Australia. Contrary to what its name suggests, the saltwater crocodile can also live in fresh water, whether in rivers, billabongs (bodies of stagnant water) or marshy areas.
Its ideal habitat is in the “Top End”, particularly around Darwin, where the climatic conditions are optimal. The Northern Territory alone is home to an estimated population of 100,000 individuals, making it an area of high concentration for this iconic species.
Did you know?
The saltwater crocodile can be found more than 150 kilometers inland. It uses river currents to travel up rivers, expanding its territory beyond coasts and estuaries.
Portrait of the Predator: The Physiognomy of the Marine Crocodile
The saltwater crocodile is the largest living saurian in the world. Adult males average between 5 and 6 meters in length, while some specimens can reach 7 meters and weigh up to 1,000 kg. In contrast, females are smaller, generally measuring between 3 and 4 meters. Its skin is thick and its color varies from gray to brown with darker mottling. One of its major assets is its powerful jaw which has between 64 and 68 teeth capable of crushing almost anything it catches.
The freshwater crocodile, or Crocodylus johnstoni, is much smaller and less aggressive than its marine cousin. The latter can be particularly territorial and does not hesitate to attack any intruder in its environment. Finally, it has developed a rare ability among reptiles: it can walk with a “high step”, that is to say by lifting its entire body from the ground. This will allow it to travel long distances on land and expand its territory.
Did you know?
Saltwater crocodiles do not chew their food. They tear their prey to pieces with violent head shakes or swallow them whole, depending on the size of the victim.
Birth in the Marshes: Reproduction and Development
Breeding of the estuarine crocodile takes place during the rainy season, usually between November and April. The courtship display is marked by territorial behaviors of the males, who defend their breeding area with force. The dominant male mates with several females in his territory. The female then builds a nest in an elevated area sheltered from the tides and lays between 40 and 60 eggs there. The temperature of the nest determines the sex of the hatchlings: temperatures between 31 and 33 degrees produce males, while temperatures outside this range produce females.
Juveniles are extremely vulnerable. Of the hundreds of eggs laid each year, very few reach adulthood, due to natural predators such as birds, fish or wild pigs. Some adults also show cannibalistic behavior and do not hesitate to attack younger individuals.
Did you know?
The survival of young saltwater crocodiles to adulthood is approximately 1% in their natural environment. The majority succumb to predators or unfavorable nest conditions.
Dark Hunter: A Versatile Predator
An opportunistic carnivore, the saltwater crocodile feeds on anything it can catch, from fish and crustaceans to sharks and other larger mammals such as kangaroos or cows. In Australia, it has even been seen attacking domestic animals such as dogs or horses. As a predator at the top of the food chain, it plays an essential role in regulating the populations of certain species.
Its hunting technique is effective: it is capable of remaining motionless for long hours, patiently waiting for its prey to come close enough to attack it by surprise. When it seizes prey, it drowns it then tears it apart with its powerful jaw.
Did you know?
Saltwater crocodiles swallow stones, called gastroliths, which help them grind food in their stomachs. These stones also play a role in balance when diving.
Saved from Extinction: Threats and Conservation Efforts
In the 1940s to 1960s, saltwater crocodiles were intensively hunted for their skins, which almost led to their extinction in Australia. Full protection of the species was established in 1970, and populations have since recovered. However, they continue to face threats from deforestation, loss of natural habitat and climate change, which disrupts nesting areas.
Today, around 60% of the world’s crocodile skin trade comes from Australia. It takes on average three crocodiles to make a medium-sized handbag. These luxury bags can sell for up to €300,000. Controlled breeding farms make it possible to meet demand while limiting the impact on wild populations. Despite this, the future of the species remains uncertain in some regions of the world, where protection is not as rigorous.
A Guardian of the Mangroves: The Key Role of the Marine Crocodile
This ultimate predator commands respect but embodies both resilience and fragility. Although feared for its dangerousness, it plays an essential role in the balance of coastal ecosystems. He is the silent guardian of mangroves and estuaries. Its preservation is essential for the biodiversity of these wetlands and for maintaining the global ecological balance.
For more information : https://www.fishipedia.fr/fr/reptiles/crocodylus-porosus