Frequently, several forms of environmental change are responsible for the disappearance of species. For example, as tropical forests are cut down, primates have progressively smaller feeding and living spaces.
They also become more accessible to hunters, who kill animals for food and trap many primates for sale as pets, research animals, and zoo specimens.
Some animal species may move into human communities when their own are destroyed. Extermination of marauding monkeys, roaming tigers, or foraging deer is easy to justify by people whose livelihood is threatened. Pollution is another form of environmental change.
Forty species of birds in the United States, including peregrine hawk, bald eagle, pelicans, and roseate terns, lay thin-shelled as a result of ingesting degradation products of and some other chlorination hydrocarbon insecticides that make their way into the food chain.
Species of salamanders in New England are dying out because the ponds in which they breed and the moist soil in which they must live are watered by acid rain (water that combines with pollutants in the air to form acid, sulfuric acid, and other corrosive compounds).
Industrial waste dumped in the Mediterranean have so depleted the oxygen supply that some species of bacteria that decompose sewage have been wiped out and the nutrient cycles disturbed. Even die ocean environment has been altered by dumping.
There are several species of birds and animals that have been exterminated or endangered as a result of humans killing the individuals for food. The Hawaiian state bird has also become extinct. The 22 finds of clams and 30 lands of fish imperiled in the United States are probably all endangered by varying combinations of naturally changing environments, pollution, and over-harvesting.
Whale are also on the endangered list. Whale hunting is often justified as supplying a source of protein for protein-poor populations. Actually, whales supply only 1% of the protein needs of any countries, such as Japan, that is actively engaged in whaling. In the Soviet Union, whale meat is used to feed animals that are raised for their pelts, such as sable and mink.
Thus, the wearer of a ranch-raised Russian sable coat may have indirectly contributed to the ultimate disappearance of the great whales. Many species have been hunted to the point of extinction for their fur, hides or feathers. These include the big cats, alligators, kimonos, quetzel birds, eastern grey kangaroos, egrets, and bids of paradise.
Many people and groups have taken measure to stop the killing of endangered species. Whether the species were killed deliberately, or by accident (in a oil pill) these groups are trying to stop the killing.
In conclusion, it can be said that endangered species can be as big as a blue whale or as small as a tiny little ant. The responsibility of saving them is on us.