At least 33,000 types of plant and 5,400 animal species are in danger of extinction—of disappearing from the world forever. More could become extinct even before they are discovered and named. One thousand of the 4,600 or so species of mammal alone are believed to be at risk. Such creatures as tigers, black rhinos, monk seals and Bactrian camels are all on the endangered list. In the past 30 years, numbers of black rhinos have dropped by 95 percent and the wild tiger population is down to about 5,000.
An endangered species is one that is at risk. These are monitored by the World Conservation Union (IUCN), an international organization that gathers information on the world’s plant and animal species. Species at risk are organized into categories. The most serious of these include the following:
- Vulnerable: a species thought to be at risk of extinction in the wild.
- Endangered: a species thought to be of the very high risk of extinction in the wild.
- Critically endangered: a species at extremely high risk of extinction in the wild.
- Extinct in the wild: a species that survives only in captivity or protected populations.
- Extinct: experts are reasonably sure that the last individual has died.
Animals become rare and endangered for a number of reasons. These include the destruction of their natural homes, climate change, hunting, and pollution.
A CHANGING WORLD
More and more of the Earth is changing as we build cities, factories, and roads. Forests are cut down, wetlands are drained, open fields disappear—and this means that animals lose their homes. Some are able to adapt, but others cannot. Tropical rainforests contain more species of plants and animals than anywhere on Earth but every year more are destroyed and it is nowhere else for these species to live.
Large numbers of animals are caught and killed by humans, sometimes for food but also for their skin, horns or shells. Although it is illegal to kill rhinos and tigers, hunting still goes on because tusks, horns and other body parts can be sold for high prices to illegal dealers. Some creatures are shot to protect domestic animals or for sport. Others are killed accidentally as a result of modern practices: many dolphins and porpoises die in fishing nets, while gentle manatees are wounded and often killed by speedboats. Parrots and tortoises are among the animals collected as pets—the beautiful hyacinth macaw is now in danger of extinction for this reason.
Pollution is another serious problem. Chemicals and oil spill poison river and sea creatures, while crop sprays and water pollution can destroy land animals and their food. Some pollutants, like carbon dioxide, contribute to global warming. Climate change can also make life impossible for animals—conditions may become too hot or too cold, water supplies can dry up and food plants no longer grow.
WHAT CAN WE DO?
Despite all the problems, conservation measures have saved some animals. The grey whale once seemed certain to become extinct, but a ban on hunting by the International Whaling Commission has allowed numbers of grey whales in the Pacific Ocean to rise to over 20,000. California condors, large birds of prey, had disappeared in the wild, but the successful breeding of the birds in captivity has led to some being released back into their natural environment. Many zoos are involved in these vital breeding programmes.
Most conservation experts agree that the best way to save animals is to protect the places where they live—their habitats. They are studying how best to develop natural reserves in areas such as rainforests and wetlands. One difficulty is that some animals need a very large area in which to live and find their food, and a reserve may not be big enough. One answer is the development of wildlife corridors—narrow strips of land linking similar reserves through which animals can travel.