Some have suggested that the distinction in how the two cougar populations comport themselves around people stems from slight regional discrepancies in anatomy and leg length. Others have proposed that the Western puma is comparatively more accustomed to hunting large animals and thus sees Homo sapiens as acceptable pickings.

Yet scientists point out that DNA analysis has revealed very little genetic difference between the Eastern and Western panther populations, which means there is no reason to believe the Florida panther is a congenital puddy tat. Certainly the animals can be ruthless with one another. Among panthers living in prime areas away from roads, said Dr. Onorato, “the No. 1 cause of death is intraspecific aggression” — one panther killing another. Some authorities suspect it is only a matter of time and sustained human encroachment before a Florida panther pounces on a Florida land speculator.

Devotees yearn to see panthers in the wild, but very few ever do. The cats are quiet, reclusive, solitary and built to blend in. On a twilight foray into known panther territory under the guidance of a naturalist, Marcy Wagner, we saw dozens of alligators with their madcap zigzagging heat-control grins, and anhingas looking like caped pterodactyl Draculas as they dried out their wings, and storks, hawks, egrets, herons and orchids worthy of being poached. We spotted fresh panther tracks in the swamp mud and even fresher panther scat, and at one point Ms. Wagner declared there was a distinct smell of “wet cat,” but whether that smell was a wading cougar, well, I have no proof of that.

Early Americans had a much easier time puma sighting, for the cats abounded across the continent. For generations the cats were shot as vermin and their hunting grounds transformed into cattle pastures, farmland or conference centers. By the late 1980s, the Florida panther population hit its nadir of about 20. “It was a recipe for entering the vortex of extinction,” Dr. Onorato said.

But with the help of the Endangered Species Act and other legislation, and with the introduction of a few Texas pumas into the area to counter the threat of so-called inbreeding depression, the Florida panther was yanked back from the vortical brink.

The panthers did their part, too, thanks to a reproductive schedule vaguely reminiscent of an unspayed house cat. Panthers can breed year round, their gestation period is 90 days, compared with a domestic cat’s 67, their average litter size of 2.5 kittens is just slightly below that of a house cat, and they nurse their young for a pet-length span of about eight weeks.

Unlike the great cats, panthers lack the vocal cords to roar, but they can purr. Among the panther’s favorite meals is an invasive species — the feral hog, brought to this continent by the Spaniards in the 16th century — but it will also eat white-tailed deer, armadillos, raccoons, small alligators and pet cats on the loose.

Pumas need lots of space. Females roam over a home range of about 80 square miles, while males patrol ranges as big as 250 square miles. For anyone driving through Florida cat country, the law demands you take it slow. If you’re lucky, you’ll see a panther — one that still has the eyes to see you.