The reptile remains protected under the federal Endangered Species Act even though it was downgraded to a "threatened" species, making it illegal to harass, poach or kill the reptiles.
"It's just one step closer to recovery, but it still has many, many threats," Fish and Wildlife Service spokesman Tom MacKenzie said. "It's still protected with the full force of federal law."
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The crocodile was on the brink of disappearing from South Florida, its only U.S. habitat, when it was originally listed as a federally endangered species in 1975. In 1976, the population was estimated at just about 300.
Scientists now estimate there are up to 2,000 American crocodiles in Florida.
"Crocodiles were a part of Florida's history for hundreds of years until human activities such as urban development, agricultural conversion, and over-hunting decimated their populations," said Sam D. Hamilton, the service's southeast regional director.
"In the past 30 years, we have made great strides in protecting this species and conserving its habitat," Hamilton said. "Today, we can celebrate their comeback."
The reclassification comes after a five-year review of the species population and the determination that there is a sustained breeding population of at least 60 female crocodiles in the wild.
Scientists believe there is enough protected land in South Florida to maintain the population or even to allow it to expand.
The reptile remains endangered in other countries, including Belize, Colombia, Costa Rica and Cuba.
The change in federal classification does not affect the crocodile's status under Florida law, where it remains listed as an endangered species, said Henry Cabbage, a spokesman for the Florida Fish and Wildlife Conservation Commission.