Scientists think there are almost nine million animal species in the world, but most have not been discovered yet. Because of this, it's hard to know how many are dying out. However, experts believe that between 900 and 9,000 species could disappear each year. While this sounds alarming, not all species are doomed—some have been brought back from near extinction with human help.

Animals are in danger for many reasons, such as hunting and habitat destruction. One example is the gray whale, which was almost hunted to extinction. In the 1940s, there were fewer than 2,000 left. (I) Thanks to protection laws, the population has grown to over 23,000. Other animals, such as lemurs and orangutans, still face serious danger due to deforestation and expanding human populations.

When a population falls to such low numbers, its long-term survival is at risk. This is because animals thrive by being diverse, and when they breed from such a tiny group, their young may be too weak to survive. The Arabian gazelle was once in trouble, but its numbers increased again thanks to protection efforts that also helped improve its gene pool. (II)

It is important that protection efforts also focus on protecting entire ecosystems and food chains. The Amur tiger, native to Russia, northern China, and Mongolia and once hunted to just 40 animals in the 1940s, was the first tiger in the world to be given full protection. (III) What helped the Amur tiger population recover so rapidly was the restriction of hunting other animals. These included bears and deer that were its natural prey.

Sometimes, helping animals helps us in other ways. In the 1960s, whales were protected. Scientists later discovered that whale waste helps feed phytoplankton—tiny ocean plants that absorb carbon dioxide. Fewer whales led to fewer phytoplankton and may have worsened climate change. Protecting whales, therefore, can support both biodiversity and the climate. (IV) Another potential benefit comes from ecotourism, which brings money to local communities while protecting the environment. In Costa Rica, it was so successful that it created many jobs, such as tour guides, and led to the building of national parks. Local businesses—from craftspeople to restaurateurs—can also benefit.

(Adapted from Skillful)