Monday, May 25, 2009
Saltwater or estuarine crocodile (Crocodylus porosus) is the largest of all living crocodilians and reptiles. It is found in suitable habitats throughout Southeast Asia, Northern Australia, and the surrounding waters. The Alligator Rivers are misnamed after the resemblance of the saltwater crocodile to alligators as compared to freshwater crocodiles, which also inhabit the Northern Territory.
The saltwater crocodile has a longer muzzle than the mugger crocodile, and is twice the length of its breadth at the base. The saltwater crocodile has fewer armor plates on its neck than other crocodilians, and its broad body contrasts with that of most other lean crocodiles, leading to early unverified assumptions that the reptile was an alligator.
An adult male saltwater crocodile's weight is 880 to 3,000 pounds (400–1,360 kg) and length is normally 4 to 5.1 metres (13–17 ft), though very old males can be 6 metres (20 ft) or more. This species has the greatest sexual dimorphism of any modern crocodilian, with females being much smaller than males. Typical female body lengths in the range of 2.1 to 3.5 metres (6.9–11 ft). The largest female on record measured about 4.2 metres (14 ft). The mean weight of the species as a whole is roughly 450 kilograms (990 lb).
The largest size saltwater crocodiles can reach is the subject of considerable controversy. The longest crocodile ever measured snout-to-tail and verified was the skin of a deceased crocodile, which was 20 feet (6.1 m) long. Since skins tend to shrink slightly after removal from the carcass, this crocodile's living length was estimated at 20.7 feet (6.3 m) and it probably weighed well over 1,200 kilograms (2,600 lb). Incomplete remains (the skull of a crocodile shot in Orissa) have been claimed to come from a 7.6 metres (25 ft) crocodile, but scholarly examination suggested a length no greater than 7 metres (23 ft). There have been numerous claims of crocodiles in the 9 metres (30 ft) range: the individual shot in the Bay of Bengal in 1840, reported at 10 metres (33 ft); another killed in 1823 at Jala Jala on Luzon reported at 8.2 metres (27 ft); a reported 7.6 metres (25 ft) crocodile killed in the Hooghly River in the Alipore District of Calcutta. However, examinations of these animals' skulls actually indicated animals ranging from 6 to 6.6 metres (20–22 ft).
Saltwater crocodiles are very dangerous animals, but data on attacks is limited outside of Australia, and estimates of human fatalities vary wildly between dozens to thousands annually. It is likely that, given this species' low population within most of its non-Australian/New Guinean range, the number of attacks is probably within the lower range of estimates. Most attacks by adult "salties" are fatal, given the animals' size and strength. In Australia, attacks are rare and usually make headlines when they do occur.
Attacks on humans:
Dr. Adam Britton, a researcher with Big Gecko, has been studying crocodilian intelligence. In so doing, he has compiled 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% of body weight in the saltwater crocodile), they are capable of learning difficult 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 clever animals that can possibly learn faster than lab rats. They have also learned to track the migratory route of their prey as the climate changes.