See What Happened to the Animals on the Original Endangered Species List

  • Indiana Bat, Myotis sodalis.Status: Endangered.
    Timothy D. Easley—AP Photo
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  • Delmarva Peninsula Fox Squirrel, Sciurus niger cinereus.Status: Delisted due to recovery, in 2015.
    Samuel R Maglione—Science Source/Getty Images
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  • Timber Wolf, Canis lupus lycaon.Status: Varied. The Gray Wolf is endangered in some portions of the mountain-prairie region, threatened in the Great Lakes region and delisted due to recovery in other areas. Recently, the Eastern Timber Wolf was found to be a separate species from the Gray Wolf, Canis lupus, and the status of the Eastern Wolf was put up for review.
    Christina Krutz—age fotostock/Getty Images
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  • Red wolves, Canis rufus.Status: Endangered except, as of 1986, a non-essential experimental population in North Carolina and Tennessee. ("Experimental" populations are those that have been reintroduced within the species' historical range but outside the regions where it is currently found. Experimental populations can be deemed either essential or inessential to the species' survival.)
    Joel Sartore—National Geographic/Getty Images
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  • San Joaquin Kit Fox, Vulpes macrotis mutica.Status: Endangered.
    Kevin Schafer—Minden Pictures/Getty Images
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  • Grizzly bears, Ursus horribilis.Status: Downgraded to 'threatened' status in 1975, with an additional non-essential experimental population in Idaho and several other regional populations under review.
    Daisy Gilardini—Oxford Scientific/Getty Images
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  • Black-footed Ferret, Mustela nigripes.Status: Endangered except, as of 1991, a non-essential experimental population in Wyoming and portions of other Western states.
    John E Marriott—All Canada Photos/Getty Images
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  • Florida panther, Felis concolor coryi.Status: Endangered.
    Joel Sartore—National Geographic/Getty Images
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  • Florida manatee, Trichechus manatus latirostris.Status: Endangered.
    Brian J. Skerry—National Geographic/Getty Images
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  • Guadalupe Fur Seal, Arctocephalus philippi townsendi.Status: Threatened.
    Richard Herrmann—Minden Pictures/Getty Images
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  • Key Deer, Odocoileus virginianus clavium.Status: Endangered.
    Danita Delimont—Gallo Images/Getty Images
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  • Columbian White-tailed Deer, Odocoileus virginianus leucurus.Status: Endangered in the area surrounding the Columbia River, though under consideration for downgrading to 'threatened' status, and delisted in 2003 due to recovery in Douglas County, Ore.
    Steven Kaufman—Photolibrary/Getty Images
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  • Sonoran Pronghorn, Antilocapra americana sonoriensis.Status: Endangered except, as of 2011, a non-essential experimental population in Arizona.
    Patricio Robles Gil/Sierra Madre—Minden Pictures/Getty Images
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By Lily Rothman

When the Endangered Species Act was approved on this day, Dec. 28, in 1973, it allowed the U.S. government to take several steps to protect the nation’s native plants and animals. One of the most famous of those measures was creating the list of endangered and threatened species.

But the list actually traces its roots to the beginning of the 20th century, when the disappearance of the Passenger Pigeon led the government to try—in vain—to keep the birds alive by further regulating the hunting of game birds, as the U.S. Fish and Wildlife Service notes. Decades later, in 1966, Congress passed the Endangered Species Protection Act, choosing a group of 14 mammal species for the first-ever official U.S. endangered species list. (The list also included dozens of birds, a couple of reptiles and amphibians, and 22 fish species.)

Looking back through that original list, it’s clear that the past half-century has been a mixed bag for the species on it. Many remain endangered, but others have been moved to “threatened” status or removed from the list entirely.

Captive Caribbean monk seal, Monachus tropicalis, at the New York Aquarium, ca.1910. (New York Zoological Society)
Captive Caribbean monk seal, Monachus tropicalis, at the New York Aquarium, ca.1910.
New York Zoological Society

The unfortunate exception to the rule is that Caribbean Monk Seal, pictured at left. In 1979, the seal was removed from the list due to extinction. In fact, the seal had not actually been seen since 1952, more than a decade before the list was drafted, but it took decades for scientists to conclude that there were no members of the species left to look for. It remains the only mammal in the first class of listed species to have gone extinct.

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Write to Lily Rothman at lily.rothman@time.com.

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