The American alligator, which some authorities said in the 1960s was so depleted that it might become extinct, is continuing to astound biologists by multiplying rapidly throughout the 10 states of its range.

The alligator population in the prime parts of the range -- Florida, Louisiana and Texas -- began rebounding some years ago, and the species has since been taken off the endangered-species list for these areas. In fact, the large reptiles have become a nuisance in some places, and controlled hunts are once again legal there.

Now specialists at the Interior Department's Fish and Wildlife Service have found that the population explosion is also occurring in outlying parts of the species' range.

An estimated 16 times as many large gators live in South Carolina as in the mid-1970s, and about 10 times as many live in Alabama. Alligator numbers are even growing on the fringes of its range, in North Carolina, Arkansas and Oklahoma.

The comeback is attributed to sustained, tight enforcement of antipoaching laws.

The wildlife service is now proposing to drop the classification of the alligator as "endangered" or "threatened" in seven states: Alabama, Arkansas, Georgia, Mississippi, North Carolina, Oklahoma and South Carolina. Instead, the ancient reptiles would be classed as "threatened by similarity of appearance."

This designation permits controlled hunting but reserves the government's right to reimpose tighter controls without going through the lengthy procedure of reclassification. Nominally it means the fringe-area gators could be threatened if they were killed and sold as, for example, South American caiman, a similar species that is legal to import but hard for inspectors to distinguish after the hides have been fashioned into leather goods.