Crocodile Scientific name,History of Crocodile,Evolution of Crocodile,Crocodile Size,speed,sex and Age,Crocodile Characteristic,Crocodile Behaviour

Hello friends,
today we talk about on nature creature Crocodile.

cientific name: Crocodylus palustris

Mass: Male: 40–200 kg (Adult)

Speed: 16 – 19 km/h (Adult, In Short Bursts, Swimming)

Order: Crocodilia

Conservation status: Vulnerable (Population stable) 

Rank: Species

Length: Male: 3.2 m (Adult), Female: 2.4 m (Adult)

The mugger crocodile (Crocodylus palustris), also called marsh crocodile, broad-snouted crocodile and mugger, is a crocodilian native to freshwater habitats from southern Iran to the Indian subcontinent.

History of Crocodile

Crocodiles have been around for 240 million years, appearing 25 million years before the first dinosaurs and 100 million years before the first birds and mammals. Crocodiles that lived 230 millions years ago were up to 40 feet long. "Our primate ancestors were ratty little things that went around stealing eggs," Dr. Perran Ross, a crocodile specialist and professor of wildlife ecology and conservation at the University of Florida, told the New York Times. "Ancestral crocodiles had basically the same body plan we see today, apparently because it works."

Crocodiles are regarded as the closest living relatives of dinosaurs. They have many dinosaur-like features including bird-like arrangements of the hip bones, and teeth that are mounted in sockets rather than being fused directly to the jawbone. Recent taxonomic analysis has reasoned that dinosaurs, crocodiles and birds should be classified in same the branch of animals.

Crocodiles are more closely related to birds than they are to snakes, geckos and other reptiles. Birds and crocodiles, for example, have sophisticated four chambered hearts, while lizards and snakes have only three chambers. A four-chamber heart boosts brain performance and offers more flexibility to changing environments than a three-chamber heart. Crocodiles display a number of bird-like behaviors such as building good nests, and brooding, protecting and fussing over their eggs.

The Egyptians revered crocodiles. Their river god Sobek is modeled after one. Entire crocodiles families were mummified and placed in sacred tombs with gold bracelets placed on their ankles. A Greek historian visiting an Egyptian Crocodileopolis saw priests feed them honey wine and cakes. Winston Churchill was among those who did not look upon crocodiles with the same affection. He once wrote "I avow...an active hatred of these brutes and a desire to kill them.

Evolution of Crocodile

Mel White wrote in National Geographic, “Today's crocodilians are often said to be survivors from the age of dinosaurs. That's true as far as it goes: Modern crocs have been around for some 80 million years. But they're only a small sampling of the crocodilian relatives that once roamed the planet---and, in fact, once ruled it. Crurotarsans (a term paleontologists use to include all croc relatives) appeared about 240 million years ago, generally at the same time as dinosaurs. During the Triassic period, crocodile ancestors radiated into a wide array of terrestrial forms, from slender, long-legged animals something like wolves to huge, fearsome predators at the top of the food chain. Some, like the animal called Effigia, walked at least part of the time on two legs and were probably herbivores. So dominant were crurotarsans on land that dinosaurs were limited in the ecological niches they could occupy, staying mostly small in size and uncommon in number. [Source: Mel White, National Geographic , November 2009].

At the end of the Triassic, about 200 million years ago, an unknown cataclysm wiped out most crurotarsans. With the land cleared of their competitors, dinosaurs took over. At the same time, huge swimming predators such as plesiosaurs had evolved in the ocean, leaving little room for interlopers. The crocs that survived took on a new diversity of forms, but eventually they lived, as their descendants do today, in the only places they could: rivers, swamps, and marshes.

Restricted ecological niches may have limited the creatures' evolutionary opportunities---but also may have saved them. Many croc species survived the massive K-T (Cretaceous-Tertiary) extinction 65 million years ago, when an asteroid dealt a death blow to the dinosaurs (except for birds, now viewed as latter-day dinosaurs) and a broad range of other life on land and in the oceans. No one knows why crocs lived when so much died, but their freshwater habitat is one explanation: Freshwater species generally did better during the K-T event than did marine animals, which lost extensive shallow habitat as sea level dropped. Their wide-ranging diet and cold-blooded ability to go long periods without food may have helped as well. With land-based dinosaurs and sea monsters gone, why didn't crocs take over the Earth once and for all? By then mammals had begun their evolutionary march toward world domination. Over time the most divergent lines of crocs died out, leaving the squat-bodied, short-legged forms we're familiar with.

Crocodile Size,speed,sex and Age

Adult crocodiles range in size from three feet to more than 20 feet, and can weigh more than a ton. Large male crocodiles reach a certain length and then they start to broaden out so they look more like a tank than a crocodile. No one knows exactly how long a crocodile can live. Specimens in zoos have survived until their late 60s but some scientists speculate that some they may reach an age of 80 years old.

In July 2012, a huge crocodile known as Lolong was officially named the largest crocodile in captivity, the Guinness World Records. Lolong measures 20.24 feet (6.17 meters) and weighs more than a ton, Guinness spokeswoman Anne-Lise Rouse said in a statement. The Guinness website said: “Lolong's weight was also measured at a nearby truck weigh-bridge and verified as approximately 1,075 kilograms. The reptile took the top spot from an Australian crocodile that measured more than 17 feet (5 meters) and weighed nearly a ton. See Saltwater Crocodiles.

Crocodiles can run at speeds up to 25 mph. Crocodile expert Rob Bredl told National Geographic, "It's a myth that they can run as fast as a horse. They are big creatures with little short legs. But they can strike with amazing speed. In the water however crocodiles can surge forward short bursts at up to 50mph by tucking their front and rear legs in and thrusting with their powerful tails." Some species can leap off the ground and stand on their hind legs to get at meat hung from a pole. Their tails are strong enough to dislocate a person's jaw with a single whack.

Telling male and female crocodiles apart is very difficult. In the old days breeders often had to wait until female gave birth to say for sure she was a female. In some cases zoologist discovered that reason why a supposed “breeding” pair of crocodiles fought rather than mated was that they were both males. Today sex is determined by flipping a crocodile on its back and reaching up is rear end.

Crocodile Characteristic

Crocodiles are considered to be more advanced than other reptiles. Their four-chambered hearts are almost as advanced as those of mammals and birds, allowing crocodiles to stay submerged underwater for as long as an hour by slowly pumping blood through their bodies. Crocodile and bird hearts have elaborate plumbing in their hearts with valves that keep oxygenated and unoxygenated blood separate. The reptile heart by contrast mixes the two kinds of blood. In cold weather alligators can saty underwater for up to 24 hours without breathing.

Crocodiles have a large chunk of skin in their throats called a palatal valve that prevents water from flowing into their lungs and drowning it when it opens its mouth. They also have muscles that pulls the liver backward, inflating the lungs. They serve the same purpose of a diaphragm in humans.

A crocodile's bony, leathery skin is so tough that many bullets can not penetrate it. Natalie Angier wrote in the New York Times, “As scientists are just beginning to appreciate, that body plan is panzer, a tropical tank from the skin in. Beneath its scaly sheath and craggy osteoderms is another layer of armor, built of rows of bony overlapping shingles, or osteoscutes, that are both strong and flexible. And beneath that formidable barrier is an immune system that merits the modifier: it is virtually immune to defeat. [Source: Natalie Angier, New York Times, October 26, 2004]

The crocodile's immune system is more powerful than that of humans. It is capable of killing the HIV virus and fending off severe infections and diseases that would kill people. “A crocodile wallows in mudholes, lagoons and other microbial Club Meds, yet it can suffer the most harrowing sort of injury - a limb torn off, its belly ripped open, its lower jaw sheared away - without so much as shedding a crocodile tear. "Crocodiles have tremendous robustness against bacterial infection," Dr. Ross said. "The sort of wound that would leave any of us severely septicemic doesn't seem to touch them." That immunological ferocity has inspired researchers at the Johns Hopkins to begin screening crocodile blood in search of new antibiotics." 

Crocodile Behaviour

Crocodiles are considered to be more advanced than other reptiles mentally and socially as well as physically. They learn things faster than other reptiles and are the only reptiles capable of producing loud sounds. Dr. Daphne Soares, a neuroscientist at the University of Maryland, told the New York Times, “They get a bad rap for being stupid little reptiles. But they're very curious, very alert, and they want to know what's going on."

Crocodiles are social animals who communicate with hisses, grunts, chirps, burps and growls and infrasonic sounds. Physical displays include head slapping, body arching and bubble blowing. Natalie Angier wrote in the New York Times, Crocodilians “will engage in sophisticated behavior that leaves most reptiles in the cold. They vocalize to each other. They squabble over status and can distinguish between friendly hominid and annoying graduate student with dart gun. In caring for their young, they outcluck a mother hen, for what hen can protect her babies by carrying them in her jaw? "They're not like big lizards," said Dr. George Amato, a geneticist at the Wildlife Conservation Society, a division of the Bronx Zoo. "It's clear when you spend time with them that they are quite complex." [Source: Natalie Angier, New York Times, October 26, 2004]

Male crocodiles are very territorial and status conscious. They establish a hierarchy that allows them live in crowded conditions and avoid battles. One scientist told the New York Times, “Crocodiles known their neighbors for miles around, and they know who's who, who's inferior, who's superior." This helps them live to ripe old ages.

Crocodiles swallow rocks. No one knows why they do this. It is believed to be related to their ancestry with birds (some birds and other animals too swallow pebbles to aid their digestion). Studies have shown that crocodiles swallow stones equivalent to one percent of their body weight no matter how big they are. In one study, a growing crocodile with only big rocks present would swallow some big stones and regurgitate some smaller one to get the body weight just right.

                                                           Thank you.