Animals World

 

 

 

There are around 2,700 known species of snake worldwide, with the snake being found on every continent apart from the polar regions, where it is too cold for the snake.

Snakes are elongated, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more joints than their lizard ancestors, enabling them to swallow prey much larger than their heads with their highly mobile jaws. To accommodate their narrow bodies, snakes' paired organs (such as kidneys) appear one in front of the other instead of side by side, and most have only one functional lung. Some species retain a pelvic girdle with a pair of vestigial claws on either side of the cloaca.

The snake can grow anywhere from 10cm in length, to the enormous anaconda snake that can reach lengths of up to 30ft long! There are two ways that snakes kill their prey, either the snake has a poisonous bite or the snake will wrap itself around the prey to constrict it.

Most species of snake inhabiting colder regions in the Northern Hemisphere, will hibernate through the cold winter months. The snake tends to mate in the spring time.

Reptiles, the class Reptilia, are an evolutionary grade of animals, comprising today's turtles, crocodilians, snakes, lizards and tuatara, their extinct relatives, and some of the extinct ancestors of mammals. Due to their evolutionary history and the diversity of extinct forms, the validity of the class is not universally supported in scientific circles, though in practice, it remains in use by some biologists and more laymen, especially in mass media. The study of reptiles, historically combined with that of amphibians, is called herpetology.

The earliest known reptiles originated around 315 million years ago during the Carboniferous period, having evolved from advanced reptile-like amphibians that became increasingly adapted to life on dry land. Some early examples include the lizard-like Hylonomus, Casineria and possibly Westlothiana, although the latter may be an advanced land-dwelling amphibian. In addition to the living reptiles, there are many diverse groups that are now extinct, in some cases due to mass extinction events. In particular, the K–Pg extinction wiped out the pterosaurs, plesiosaurs, ornithischians, and sauropods, as well as many species of theropods (e.g. tyrannosaurs and dromaeosaurids), crocodyliforms, and squamates (e.g. mosasaurids).

There are numerous species of bird found in a wide variety of habitats all around the world. Birds are one of the most thriving groups of animals on the planet as they generally have their habitat (the skies) to themselves.

Birds can be easily distinguished from other animals due to their sharp, pointed beaks, thin legs, wings and feathers covering their bodies. Although all bird species have wings, some are actually flightless animals that only use their wings for balance and not for flying. Where other birds, such as penguins, use their wings for swimming.

Birds are often omnivorous animals, generally eating nearly anything that they can find. Most species of bird survive on a diet primarily consisting on insects and plants such as fruits, nuts, berries and seeds.

Birds are also distinctive in the fact that they lay eggs in a similar way to other animal groups such as fish and reptiles. Birds often make nests in the trees or on the ground in which to lay their eggs.

Animals are multicellular, eukaryotic organisms of the kingdom Animalia (also called Metazoa). Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their lives. Most animals are motile, meaning they can move spontaneously and independently. All animals must ingest other organisms or their products for sustenance (see Heterotroph).

Most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals are divided into various sub-groups, some of which are: vertebrates (birds, mammals, amphibians, reptiles, fish); molluscs (clams, oysters, octopuses, squid, snails); arthropods (millipedes, centipedes, insects, spiders, scorpions, crabs, lobsters, shrimp); annelids (earthworms, leeches); sponges; and jellyfish. 

By wikipedia.