Crocodiles

Dinosuchus

Deinosuchus ("terrible crocodile") is an extinct crocodile from the late Cretaceous of North America that for decades was known as the largest crocodile that ever lived. Deinosuchus is known primarily from skull material, and recent studies have reduced its projected length. A number of other giant crocodiles, including Sarcosuchus (the "SuperCroc"), Purussaurus and Rhamphosuchus, may now exceed it in size, though comparison is difficult because only the SuperCroc is known from a largely-complete skeleton.

The skull of Deinosuchus measures more than 2 m (6 ft 7 in) from front to back and has a broad rather than narrow snout. Recent studies have reduced the estimate of the animal's total length from more than 15 m (50 ft) to between 10 and 12 m (33 & 40 ft). Even at this reduced estimate, Deinosuchus is much larger than the saltwater crocodile, of Australia, and Southern and Southeast Asia, which is the biggest living reptile.

The proportions of Deinouchus are similar to the skull of today's Nile crocodile, which specializes in hunting fish but also readily preys on large animals like the antelope and zebra.

Deinosuchus probably lurked in rivers or swamps, waiting for prey to come and drink from the water's edge. It would grab the victim in its massive jaws, studded with long but not especially sharp teeth, and then drag it into the water to drown, or perhaps spin around lengthwise like a top, to tear of chunks of flesh (the "death roll"). Its prey probably included dinosaurs, large fish, and swimming reptiles.

Deinosuchus has been discovered in both freshwater and marine deposits.

The type species, Deinosuchus hatcheri was discovered by Holland at Willow Creek, Montana, in the Judith River Formation. Material from Big Bend National Park in Texas was originally assigned to the Phobosuchus genus in 1954 by Colbert and Bird, but is now assigned to a Deinosuchus species, D. riograndensis. Specimens have also been found in Alabama, Georgia, New Jersey, North Carolina, and Wyoming.

Originally classified in the Crocodylidae family, a better skull specimen indicates it is most likely a basal alligator in the superfamily Alligatoroidea.

Crocodiles (Crocs)

A crocodile is any species belonging to the family Crocodylidae (sometimes classified instead as the subfamily Crocodylinae). The term can also be used more loosely to include all members of the order Crocodilia: i.e. the true crocodiles, the alligators and caimans (family Alligatoridae) and the gharial (family Gavialidae).

The crocodiles (colloquially called crocs), are large aquatic reptiles that live throughout the Tropics in Africa, Asia, the Americas and Australia. Crocodiles tend to congregate in slow-moving rivers and lakes, and feed on a wide variety of living and dead mammals and fish. Some species, notably the Saltwater Crocodile of Australia and the Pacific islands, have been known to venture far out to sea. They are an ancient lineage, and are believed to have changed little since the time of the dinosaurs.

The larger species of crocodiles can be very dangerous to humans. The Saltwater and Nile Crocodiles are the most dangerous, killing hundreds of people each year in parts of South-East Asia and Africa. American Alligators, and possibly the endangered Black Caiman, are also dangerous to humans.

Crocodiles are very fast over short distances, even out of water. They have extremely powerful jaws and sharp teeth for tearing flesh, but cannot open their mouth if it is held closed, hence there are stories of people escaping from the long-snouted Nile Crocodile by holding its jaws shut. Indeed, zoologists will often subdue crocodiles for study or transport by taping their jaws or holding their jaws shut with large rubber bands cut from automobile inner tubes. All large crocodiles also have sharp welters and powerful claws. They have limited lateral movement in their neck, so on land one can find protection by getting even a small tree between the crocodile's jaws and oneself.

Crocodiles are ambush hunters, waiting for fish or land animals to come close, then rushing out to attack. As cold-blooded predators, they can survive long periods without food, and rarely need to actively go hunting. Despite their slow appearance, crocodiles are the top predators in their environment, and various species have been observed attacking and killing lions, large ungulates and even sharks. A famous exception is the Egyptian Plover which enjoys a symbiotic relationship with the crocodile. The Plover feeds on parasites that infest the crocodile's mouth and the reptile will open its jaws and allow the bird to enter to clean out the mouth. The crocodile's bite strength is up to 3000 pounds per square inch, comparing to just 100 psi for a large dog.

The largest species of crocodile, also Earth's largest reptile, is the Saltwater Crocodile, found in northern Australia and throughout South-east Asia.

Crocodiles eat fish, birds, mammals and occasionally smaller crocodiles.

Wild crocodiles are protected in many parts of the world, but they also are farmed commercially. Their hide is tanned and used to make leather goods such as shoes and handbags, whilst crocodile meat is also considered a delicacy in many parts of the world. The most commonly farmed species are the Saltwater and Nile crocodiles, while a hybrid of the Saltwater and the rare Siamese Crocodile is also bred in Asian farms. Farming has resulted in an increase in the Saltwater Crocodile population in Australia, as eggs are usually harvested from the wild, so landowners have an incentive to conserve crocodile habitat. Crocodiles are more closely related to birds and dinosaurs than to most animals classified as reptiles (though all of these are thought to probably be more closely related to each other than to Testudines (turtles and tortoises), and have correspondingly unusual features for reptiles, such as a four-chambered heart.

source: wikipedia.org