Sunday, April 23, 2006

Dinosaurs

Dinosaurs lived on the earth millions of years ago even before the human life came into existence. They belong to the mezosoic era. The Dinosaurs are reptiles and most of them hhed from eggs. Predominantly the dinosaurs are herbivorous and fed on plants. Some kinds were carnivores also. Some dinosaurs were 100 ft long and abt 50 ft tall. They are land dewellers and never lived in water. There are no concrete proofs on how the dinosaurs sounded or how they mated. The fossils are found all over the world. They had thick bumpy skin. Its believed that they became extinct because of the environmental changes due to an asteroid that hit the earth. Its very difficult to acertain the sex of the dinosaur from its fossils. The oldest dinosaur is 'EORAPTOR'.

Monday, April 10, 2006

DOLPHINS

Dolphins belong to the family Delphinidae. They are very social creatures. They mainly rely on their sense of sound to understand the world around them.

Dolphins are carnivores. They feed on octopus, squids and fish. There are many varities of dolphins like Spotted Dolphin, Rough-toothed Dolphin,Bottlenose Dolphin, Pacific bottlenose dolphin, Spinner Dolphins. Dolphins are often found in small groups.

Dolphins possess a beak. The dolphin's skin is completely smooth allowing the dolphin to move easily through the water, and also reduce heat loss. Their skin may bear marks from other dolphins, due to playing or mating. Dolphins use their powerful tail in an up and down motion to move through the water. They also use their tails when hunting. Their teeth are interlocking rows of conical pegs, suitable for holding slippery fish. The dolphin's eyes produce a special slippery secretion which protects the eyes from foreign objects and water friction. Their foreheads slope almost uniformly to the tip of their beek. Dolphins breathe through their blowhole located at the top of their head.

Dolphins are mammals. Dolphins carry their young inside their womb and gestation is about 12 months for a bottlenose. The dolphin calves are born tail first and are nursed by the mother for one to two years. The mother helps the calf to catch her first breath.

The dolphin's anatomy helps it to swim very fast in water. Its smoothe slippery skin, wings and tail are desinged in a way to achieve high speeds.