The International Union for Conservation of Nature (IUCN) is considered the global authority on all aspects of the natural world, including the conservation status of animal species. And with tens of thousands of animal species in its catalogue, there are plenty of animals to keep an eye on.

“Endangered” is a classification within this system. If an animal is endangered, it means they’re at “very high” risk of total extinction in the wild. (This is only one step away from the last category in the IUCN’s list—critically endangered—which mean the species is all but extinct.)

And while plenty of incredible species have gone extinct over the years, some come close to the edge and then bounce back. Local conservation efforts can help here, such as the U.S. Endangered Species Preservation Act of 1966, and the Endangered Species Act of 1973, both of which have helped protect animals from extinction—here in the states and across the world.

1. Manatees

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Also known as “sea cows,” manatees come in three varieties: West Indian, West African, and Amazonian. And by 1967, the United States Fish and Wildlife Service had listed them all as endangered.

Did you know that manatees have no natural predators? It’s true! While we tend to view herbivores like these as prey for things like sharks or killer whales, manatees live in different waters than these predators, so they don’t really run across them too often.

But as shallow-water swimmers, what manatees do run across are plenty of humans. Like many animals on this list, the manatee’s struggle can be directly linked to human activity, such as commercial fishing accidents, pollution, climate change, and more factors that disrupt their ecosystem.

Things looked grim—but conservation efforts throughout the latter half of the 20th century would eventually pay off. Population numbers began to rise, and eventually, the IUCN downgraded the status of all three manatee species from endangered to merely vulnerable.

2. American Alligators

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If you live in the marshy wetlands of the American South, you’re probably well-acquainted with alligators. These large, hulking reptiles lived happily for millions of years in the wild—until, of course, humans came along and ruined things.

In the past, people didn’t really understand alligators or the vital role they played in the wetland ecosystem. They were hunted for sport and hunted out of fear. Combined with growing industrialization that destroyed their habitats slowly over time, the future of these majestic creatures was in doubt. Per the 1966 Endangered Species Preservation Act, American alligators were officially considered endangered.

Of course, American alligators are long past the endangered phase. Conservation efforts have been quite successful in restoring their populations, and as of today, the American alligator is listed as a species of “least concern” by conservation experts.

3. Northern Elephant Seals

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Much like manatees, the northern elephant seal is a seafaring giant, coated in a thick layer of blubber and weighing between 1,000 and 4,000 pounds. These are the largest seals in the northern hemisphere and can be seen migrating from the cold Alaskan shores to the warmer waters of the California coast.

But the northern elephant seal almost didn’t make it. As rich sources of fat, blubber, and hide, these seals were prime targets for hunters looking for fuel in the icy north. They were so aggressively hunted that they were thought to be extinct in the late 1800s until small, isolated colonies began to crop up. It was at this point that conservationists realized that they had a chance to bring this noble species back from the brink.

Thanks to a multi-national conservation effort to protect these seals (which involved cracking down on seal hunting), the northern elephant seal began to bounce back. Recent estimations put their total population in the wild at 100,000.

4. Bald Eagles

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The bald eagle is one of the most iconic animals in American history, being chosen as the country’s national symbol back in 1782. In those days, bald eagle populations were plentiful, and it was common to see them soaring majestically.

But everything changed after World War II. Shortly after the war, a new chemical called DDT became popular, with plenty of advocates pushing for it as a commercial and household pesticide. This push would have terrible, long-lasting effects on the environment—including our bald eagles. DDT caused defects in bald eagle eggs and prevented much of the population from growing. Eventually, there were fewer than 500 nesting pairs alive in the lower 48 states.

Thanks to the banning of DDT and rise of other environmental protections, bald eagles made a healthy comeback. Recent estimates say that there are now over 5,000 nesting pairs in the lower 48 states, not counting those living in Canada.

Preserving Natural Wildlife

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Research tells us that certain animals are “selected” for extinction by virtue of survival of the fittest. But others (including all on this list) face much bigger threats from human activity. And while we humans can’t protect every species out there from extinction, we need to do our part to protect the ones we’re directly harming with our day-to-day lives.