In March 1987, Florida biologists released twelve radio-collared wild hogs into the Everglades to see if they could feed endangered Florida panthers by giving them something easy to kill. Bears ate two. An alligator ate one. Hunters poached three. A panther finally killed one after 117 days. By then, most of the hogs were already dead from everything except the animal they were supposed to feed.
The experiment came from a real problem. Florida panthers living south of Alligator Alley in the Fakahatchee Strand and the southern Big Cypress were in worse physical condition than panthers to the north. Food habits studies by the Florida Game and Fresh Water Fish Commission showed why. Panthers north of the highway ate mostly white-tailed deer and wild hogs, large prey with high caloric return. Panthers south of the highway were living on raccoons and armadillos, smaller animals that provide less energy per kill. The southern panthers were nutritionally stressed in the commission's language. In plain language, they were not getting enough to eat.
The idea was to test whether releasing hogs directly into occupied panther home ranges could supplement the prey base. The commission selected twelve castrated, pseudorabies-free wild hogs, fitted them with radio collars equipped with mortality signals, and split them into two groups.
On March 27, six hogs were released into the Fakahatchee Strand State Preserve within one kilometer of a radio-collared adult female panther. On March 28, six more were released in the privately owned Golden Gate area south of Alligator Alley within 200 meters of a different radio-collared female panther and her eight-month-old male kitten. The researchers monitored the hog collars every other day from the air, flying the same telemetry routes they used to track panthers. When a collar transmitted a mortality signal, a ground crew went in the same day to examine the carcass.
The swamp ate the experiment.
Two hogs were killed by black bears. One was killed by an American alligator. One was found eviscerated and partly covered with debris, which is consistent with a panther kill but could also have been a bobcat or another bear. Three hogs were killed by hunters, identified by knife marks on the radio collars. Two collars failed entirely and the hogs were never recovered. Two more collars were found on hog carcasses with no sign indicating what killed them.
One panther killed one hog. It happened 117 days after the release, nearly four months into the experiment, and was preceded by the deaths of at least eight of the other eleven hogs. The kill was made by a radio-collared adult male panther, not by either of the two females the hogs had been released next to. The females had home ranges of 160 to 350 square kilometers. The hogs stayed within four kilometers of their release sites.
The math was simple and unfavorable. The panthers they were meant to feed moved across enormous ranges while the hogs sat in one small area. The chances of a specific panther encountering a specific hog on a given night were low despite the radio locations showing both species in close proximity.
David Maehr and his co-authors at the commission published the results in the Florida Field Naturalist and concluded that the low number of released hogs made definitive conclusions impossible, but that the one confirmed panther kill suggested very large-scale releases might increase the prey base.
They also noted the obvious problem. The biological consequences and economic costs of large releases of hogs makes this a debatable management alternative. Releasing hundreds or thousands of hogs into the Everglades to feed panthers would simultaneously create an invasive species problem in a national preserve that was already struggling with feral hog damage to native vegetation and hydrology.
The experiment was never repeated at scale. The panthers south of Alligator Alley continued eating raccoons and armadillos. The genetic rescue that eventually saved the Florida panther population came not from supplementing the prey base but from supplementing the gene pool, when eight Texas cougars were brought in eight years later. We covered that story on this page with TX-101.
Twelve hogs were released to feed panthers. Bears, alligators, hunters, bobcats, and unknown causes killed eleven of them. One panther ate one hog four months later. The swamp took everything first because the swamp does not care about experimental design, and every predator south of Alligator Alley was hungry, not just the one the experiment was trying to feed.
Source: Maehr, D.S. et al. (1989). "Fates of Wild Hogs Released into Occupied Florida Panther Home Ranges." Florida Field Naturalist 17(2):42-43.
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