Saltwater crocodileScientific Name Crocodylus porosus           

Conservation Status Least Concern

Appearance

Saltwater crocodiles have a wider snout than most crocodiles. Their skull may reach up to 75cm (30in) in length. A pair of ridges runs down this snout from the eyes. Their broad body led to early reports that they were a variety of alligator. They have oval shaped scales. Their longs are short and strong.

Juveniles are pale yellow in colour with black stripes along their body and tail. When they mature most become a dark greenish colour. Some may remain a pale yellow though or may be quite dark. They have light tan and grey areas on some parts of their body.  The underside on both juveniles and adults is white or tallow. They have a grey tail with dark bands.

At hatching this species measures 25-30cm (9.8-11.8in). The average weight of a hatchling is 70g (2.5 oz). Males average 4.3-5.2m (14-17ft) but may reach 6m (20ft) long. Their weight can be up to 1,360kg (3,000lb). Due to poaching the larger crocodiles are now rare.

Lifespan                                                                                  

Life expectancy is generally accepted to be upwards of 70 years with some individuals managing to exceed 100 years of age.

Diet

The saltwater crocodile is a carnivore. They prey upon almost anything they can get their teeth on. As hatchling they will feed upon small fish, frogs, insects and small aquatic invertebrates. As they grow into adults they will eat snakes and lizards, crabs, fish, bats, birds and mammals. These may include monkeys, orangutans, deer, jackals, dholes, kangaroos and dugongs. Some crocodiles have been seen feeding upon bull sharks. Only the Asian elephant is safe from these crocodiles. On occasion they have been seen taking out freshwater crocodiles.

They eat by seizing their prey in the draws and then drowning it in deep water. They will then death roll (a turning motion that tears off meat) to break the food into smaller chunks.

Habitat

Saltwater crocodiles are found in India, Northern Australia, Myanmar and New Guinea. Previously the species was found throughout Thailand, Laos, China, Malaysia, and Vietnam but they are now extinct in these areas. Long into the past a population could be gound reaching to the east coast of Africa. There is also evidence that they are extinct in Cambodia where they were once found. Some small populations are reported in the South Pacific.

This species can be found lurking in deep, dark, murky water. Most of their habitat is the estuary areas. They can live in both salt and fresh water. On occasion they have been seen swimming in the open ocean.

Reproduction

Mating occurs during the wet season. The male patrols a stretch water and makes sure that no males enter it. When a female and male come together to mate they rub their heads and bodies together. They will then Saltwater crocodilemate in the water.

The female will find a spot alongside a tidal river or in a freshwater area where they can make a mound of mud and vegetation where their eggs can be deposited. Into this they typically lay 40-60 eggs with some unusually large clutches including 90. The nest may measure up to 80cm high.

Mother crocodiles are highly vigilant and look over the eggs for the 80-98 days that it takes for the eggs to hatch. Predation or flooding may mean the nest is lost.

If the eggs are incubated below 30oC they will be female. Above 32o C they will be males. When they hatch they begin to yelp. The female will then dig them up and carry them to the water.

While the mother spends months looking over the young crocodiles only 1% will make it to be adults. After 8 months the young begin to strike out on their own. At 2.5 years of age they begin to start marking out a territory for themselves. Sexual maturity is achieved at 10 years old.

Behavior

Young saltwater crocodiles are preyed upon by monitor lizards, predatory fish, aquatic birds and raptors, adult crocodiles, tigers and leopards.

Saltwater crocodiles are prone to entering the ocean. They have salt glands that enable them to survive in the ocean. Ocean currents are used by the crocodiles to move across long distances. On occasion they spend so long at sea that barnacles begin to grow on their scales.Saltwater crocodile

Adult males maintain a territory which they allow females to pass through but stop other males from entering.

This species is quite lethargic choosing to back most of the day and going months at a time between feeds. They tend to stay away from land except when pasting.

Quick facts

The largest crocodile in the world is a 2,000kg (4,440lb), 7.1m (23ft) long male living in Odisha, India. This statistic was recognized by Guinness World Records.

This species also goes by the names saltie, estuarine crocodile and Indo-Pacific crocodile.

Saltwater crocodiles are farmed in Australia for their meats and eggs.

Some estimates suggest that saltwater crocodiles attack 20-30 people per year.

Photo Credits:

Top Public Domain

Middle By Scott Sandars from Melbourne, Australia (Flickr) [CC BY-SA 2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons

Bottom Public Domain