Endangered Species Act

How this 1973 law protects animals

A manatee glides through clear, warm spring water in Florida. A grizzly bear catches a juicy trout in Yellowstone National Park. A bald eagle soars near the U.S. Capitol in Washington, D.C.

A little over 50 years ago, these species were among the first group of animals that received protection from the federal (or national) government in the United States. Once nearly extinct, all three species bounced back thanks to a law called the Endangered Species Act.


Native American people have lived alongside these animals for thousands of years. Although the people changed the animals’ environment—for example, they burned land for farming—they were usually careful not to hunt too many animals, making sure that the population numbers would remain healthy.

But European settlers arriving in the early 1800s had a different relationship to the land: They cut down forests to clear space for their houses and towns, and they hunted as many animals as they wanted for food, materials, and even sport.

By the end of the 1800s, Americans could see that some species were in big trouble: Due to overhunting, the American bison population went from about 30 million to just a few hundred in less than a century. The passenger pigeon, once the most abundant bird in North America—numbering in the billions—disappeared from the skies in just a few decades because so many people hunted them for sport.

These animals motivated Congress to pass the first federal wildlife-protection law in 1900 called the Lacey Act, which made it a crime to buy or sell animals that were illegally hunted. But the protection was too late for the passenger pigeon, which went extinct in 1914.

In the next few decades, Congress passed more legislation to try to protect animals, but many populations continued to decline.


In 1966, Congress signed the Endangered Species Preservation Act, which set aside land and water for conservation of dwindling fish and wildlife populations. But this act didn’t include any rules on how to protect these species, so three years later, Congress renamed the act to the Endangered Species Conservation Act and expanded it to create hunting restrictions. It also included protections for endangered species that live outside of the United States.

Then in 1969, an oil rig off the coast of California ruptured, creating the worst oil spill in the United States at the time. It dumped three million gallons of oil into the ocean; covered the beaches in slick, black oil; and killed thousands of animals. Then people found out that the government had given the company special permission not to follow safety regulations. If it hadn’t, the spill could have been avoided.

Americans were upset, and when President Richard Nixon walked along the black-stained beach, he knew things had to change. He created the Environmental Protection Agency in 1970, and he pushed Congress to pass the Endangered Species Act in 1973.

The act officially defined what it meant to be an endangered or threatened species, protected plants and invertebrates for the first time, restricted hunting any animals on the list, and provided funding to save the species. And most importantly, it protects the habitats that these plants and animals depend on to survive.

“Nothing is more priceless and more worthy of preservation than the rich array of animal life with which our country has been blessed,” Nixon said when he announced the legislation. The first year, 78 animal species were added to the list and given protection under the Endangered Species Act.


Scientists count the number of each species in as many places around the world as possible to estimate its population. Then they consider the health of its habitat, the way the species is used by people, whether it's affected by disease, and other factors to figure out if it's likely to go extinct in the wild. A species is considered threatened if scientists have evidence that shows that the species will soon become endangered. Once a species is listed, the law makes it illegal to capture, hunt, shoot, or harm that animal without a permit.

Two government groups manage the endangered species list: The U.S. Fish and Wildlife Service takes care of land and freshwater species, while the National Oceanic and Atmospheric Administration looks after saltwater species.

When a species is added to the endangered species list these teams first investigate why the species is endangered. The most common causes are habitat destruction, disease, or overuse of animals for human purposes, like overfishing. Once the main problem has been found, the team can build the best plan to help the species. (If it’s a foreign species, the government can restrict the sale of the species or its parts in the United States.)

Once on the list, the species go through three phases. First the experts reduce or stop the main threat to the species, which might mean limiting the amount of trees being cut down or prohibiting the use of certain chemicals on farms. Next the recovery teams carefully monitor the population, and they might help increase numbers by breeding the animal. If the species is found to be no longer at risk based on its population size, habitat stability, and threat reduction, the species is taken off the list—success!

American alligators, Channel Island foxes, peregrine falcons, and bald eagles were all species that were in trouble and successfully went through this process. But saving species isn’t fast or easy: Only one percent of species on the list have been removed, and a study found that on average it takes a species about 25 years to recover.


The law still has some critics: They don’t like that it limits how land can be used, which some people think hurts businesses and private landowners. They also debate what should be considered an animal’s habitat: For example, gray wolves once roamed across almost all of North America, but today they live in a fraction of that range. The wolves’ population is stable, but should they be reintroduced to their historic homeland?

Today the Endangered Species Act is actively protecting and conserving over 2,000 species of plants and animals, including animals whose range includes the United States like humpback whales and green sea turtles; native species like black-footed ferrets and Karner blue butterflies; and even foreign species like giant pandas and tigers. About 99 percent of species listed avoid going extinct, and a study by the Center of Biological Diversity found that over 200 species would have gone extinct if not for the law.

So next time you see a manatee, grizzly bear, or bald eagle, thank the Endangered Species Act!

<p>The sale of tiger parts in the United States is banned under the law.</p>

The sale of tiger parts in the United States is banned under the law.

John Downer Productions / NPL / Minden Pictures