An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters. Also it could mean that due to deforestation there may be a lack of food and/or water. The International Union for Conservation of Nature (IUCN) has calculated the percentage of endangered species as 40 percent of all organisms based on the sample of species that have been evaluated through 2006. The IUCN groups all threatened species for their summary purposes. Many nations have laws offering protection to conservation reliant species: for example, forbidding hunting, restricting land development or creating preserves. Only a few of the many species at risk of extinction actually make it to the lists and obtain legal protection. Many more species become extinct, or potentially will become extinct, without gaining public notice.Since 1600 about 500 species of animals have become extinct.
The dodo has become a symbol of extinction. It was a turkey-sized flightless pigeon which lived on the island of Mauritius. When sailors landed on the island for the first time in the sixteenth century, they killed the helpless bird for food. The dodo's eggs and young were eaten by dogs, cats, pigs, rats and monkeys which man had introduced to the island. The dodo, unused to predators, very quickly declined in numbers - and it was extinct by 1681.
