Information about Saltwater Crocodile

Saltwater Crocodile
Conservation status
Least Concern
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Sauropsida Order: Crocodilia Family: Crocodylidae Subfamily: Crocodylinae Genus: Crocodylus Species: C. porosus
Binomial name
Crocodylus porosus (Schneider, 1801)
Range of the Saltwater Crocodile in black Range of the Saltwater Crocodile in black

The Saltwater or Estuarine Crocodile (Crocodylus porosus) is the largest of all living reptiles. It is found in suitable habitat throughout Southeast Asia and northern Australia. Saltwater crocodiles are known in the Northern Territory of Australia as 'salties'. The Alligator Rivers are misnamed after the resemblance of the 'saltie' to alligators as compared to freshwater crocodiles, which also inhabit the Northern Territory.

Anatomy and morphology

An average adult male saltwater crocodile is typically 4.8 to 5.5 metres (15.75 to 18 feet) long, and weighs around 500 kg (1100 lb). However the maximum size of the saltwater crocodile is well over 7 metres (23 feet) in length and over 2.5 metric tons (3300 lb). The largest living saltwater crocodile is a 7.1 metre (23.3 ft) crocodile in Orissa, India. The largest confirmed estuarine crocodile is a 8.6 metre (28.3 ft) crocodile shot in Australia,^[1] with larger records unconfirmed.^[2] Females are much smaller than males, with typical female body lengths in the range of 2.5–3 meters (8.2 to 9.8 feet). The saltwater crocodile has fewer armor plates on its neck than other crocodilians, and its broad body contrasts with most other lean crocodiles, leading to early unverified assumptions the reptile was an alligator.^[3]

Distribution

Saltwater crocodiles are severely depleted in numbers throughout the vast majority of their range, with sightings in areas such as Thailand, Cambodia, Laos and Vietnam becoming extremely rare and the species may in fact even be extinct in one or more of these countries. With that said, it is also the least likely of crocodilians to become globally extinct due to its wide distribution and almost pre-colonial population sizes in Northern Australia and New Guinea. In India this crocodile is extremely rare in most areas but is very common in the north eastern part of the country (mainly Orissa and the Sunderbans). The population is sporadic in Indonesia and Malaysia with some areas harboring large populations (Borneo for example) and others with very small, "at risk" populations (the Philippines). The saltwater crocodile is also present in very limited portions of the South Pacific, with an average population in the Solomon Islands, a very small & soon to be extinct population in Vanuatu (where the population officially only stands at three) and a decent but at-risk population in Palau (possibly rebounding).

Saltwater crocodiles have earlier prevailed as far west as the east coast of Africa at the Seychelles Islands, and all the way up the coast of Africa . These crocodiles were once believed to be a population of Nile crocodiles, but they were later proven to be Crocodylus porosus.

Habitat

Saltwater crocodiles generally spend the tropical wet season in freshwater swamps and rivers, moving downstream to estuaries in the dry season, and sometimes traveling far out to sea. Crocodiles compete fiercely with each other for territory, with dominant males in particular occupying the most eligible stretches of freshwater creeks and streams. Junior crocodiles are thus forced into the more marginal river systems and sometimes into the ocean. This explains the large distribution of the animal (ranging from the east coast of India to northern Australia) as well as it being found in odd places on occasion (such as the Sea of Japan, for instance). Saltwater crocodile speed underwater can be 15 to 18 miles per hour in short bursts, but when cruising can go 2 to 3 miles.

Behaviour

The saltwater crocodile is an opportunistic predator capable of taking animals up to the size of an adult male water buffalo, either in the water or on dry land. Juveniles are restricted to smaller items such as insects, amphibians, crustaceans, small reptiles and fish. The larger the animal grows, the greater the variety of items that it includes in the diet, although relatively small prey still make up an important part of the diet even in adults. Saltwater crocodiles can take monkeys, kangaroo, wild boar, dingos, goannas, birds, domestic livestock, pets, water buffalo, gaur, leopards, sharks^[4], and humans, among other large animals as well. Generally very lethargic – a trait which helps it survive months at a time without food – it typically loiters in the water or basks in the sun through much of the day, usually preferring to hunt at night. Capable of explosive bursts of speed when launching an attack from the water, many species of crocodile are also capable of fast land-movement. Many crocodiles are capable of explosive charges that can carry them nearly as fast as a running human. The 23 species of crocodile can travel over land using the belly crawl, the walk, the high-walk, and the gallop. The reported stories of crocodiles being faster than a race horse for short distances across the ground are little more than urban legend.

As an ambush predator, it usually waits for its prey to get close to the water's edge before striking without warning and using its great strength to drag the animal back into the water. Most prey animals are killed by the huge jaw pressure of the crocodile, although some animals may be incidentally drowned. It is an immensely powerful animal, having the strength to drag a fully grown water buffalo into a river, or crush a full-grown bovid's skull between its jaws.

In its most deadly attack, called the "Death Roll," it grabs onto the animal and rolls powerfully. This is designed to initially throw any struggling large animal off balance making it easier to drag it into the water. The "Death Roll" is also utilized as a method for tearing apart large animals once they are dead.

The saltwater crocodile, is one of the major animals involved in attacks on humans in Southeast Asia and Australia and is responsible for about 300 deaths annually. This is the highest number for any crocodilian in the world, therefore the saltwater crocodile is considered as the most dangerous crocodilian to humans. In addition, it has been responsible for the deaths of 12 people between 1975 and 1988 in Northern Australia alone.

Intelligence

Dr. Adam Britton, a researcher with Big Gecko, has been studying crocodilian intelligence. In so doing, he has composed a collection of Australian saltwater crocodile calls, and associated them with behaviors. His position is that, while crocodilian brains are much smaller than those of mammals (as low as 0.05% in the saltwater crocodile), they are capable of learning hard tasks with very little conditioning. He also infers that the crocodile calls hint at a deeper language ability than currently accepted. He suggests that saltwater crocodiles are smart, clever animals that can possibly learn faster than lab rats.

Bibliography

• Crocodile Specialist Group (1996). Crocodylus porosus. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 09 May 2006.

References

Marshall, Ben "The Crocodile" New York Publishers Inc. 1999

See also

• Crocodile attacks

External links

• Recent Crocodile Attacks in Australia
• Australian Saltwater Crocodile Photos and attack file
• Saltwater crocodile calls from Dr. Britton's crocodilian.com site
• Brief discussion from Dr. Britton and others discussing dromaeosaurid intelligence