Crocodiles are large reptiles that live in tropical areas of the world. There are three main species of crocodile: the American crocodile, the Australian saltwater crocodile, and the Nile crocodile. Crocodiles are predators that hunt and kill their prey with their powerful jaws and sharp teeth. They can grow up to 20 feet (6 meters) long and weigh over 2,000 pounds (900 kilograms).
Crocodiles have been around for millions of years and are one of the oldest groups of reptiles. They first appeared during the Triassic period, about 200 million years ago. Crocodiles evolved from a group of reptiles called archosaurs. The earliest crocodiles were small animals that lived in freshwater environments such as ponds and rivers. Over time, they became larger and began to inhabit saltwater habitats such as estuaries and coastal areas.
Today, there are only about 20 species of crocodilian alive. This is a very small number compared to the hundreds of different species that once lived on Earth. Many crocodylians went extinct during the Cretaceous-Tertiary mass extinction event 65 million years ago, when dinosaurs disappeared from the planet. Crocodilians survived this event because they were able to adapt to changing environmental conditions better than other reptiles did at the time.
Crocodilians are ectothermic animals, meaning that they rely on external sources of heat to regulate their body temperature. They basking in the sun or lying in warm water to raise their body temperature when it is cold outside. When it is hot, they seek shade orcool themselves off by opening their mouths and flicking out their tongues . Because they cannot sweat like mammals do , crocs must be careful not to overheat themselves . If a croc gets too hot , it will start panting heavily with its mouth open to help cool down its body .
A fully grown saltwater crocodile can measure up20 feet long from nose tip top tail , making it oneof longest extant reptile species . Females tend be smaller than males 16 – 18 ft ( 4 9 – 5 5 m ) versus 23 ft ( 7 m ) on average but both sexes reach comparable sizes extreme cases . On average , adult male salties weight 1 tonne ( 0 91 tonnes ), with unconfirmed reports specimens weighing as muchas 2268 kg ( 5000 lb ) captive individual “ Lolong ” was measured at 6 3 m ( 20 ft 6 in ) length weighed 1575 kg ( 3480 lb ) making him heaviest ever recorded specimen hands down though he died shortly thereafter due stress captivity