Perhaps no animal’s current predicament better illustrates the negative impact of insularity and the need for connectivity than that of the Florida panther. In contrast to the jaguar of Mexico and Central America that is still connected throughout its range (see Paseo Pantera, Path of the Panther), the Florida cougar has become confined to an “island” in and around the Florida Everglades, imprisoned on the north by a sea of human development.
The North American cougar (Puma concolor, meaning cat of a single color) goes by a variety of common names, including catamount, mountain lion, and puma in addition to panther and cougar. In south Florida, the cat is almost always called “panther.” With the settlement of the U.S., the cougar along with other predators was mostly eradicated over much of its eastern range by the late 1800s through hunting and loss of habitat. By 2011, the Fish & Wildlife Service declared the eastern cougar extinct. Removal of the eastern cougar from the endangered species list was finalized in 2018. Some wildlife experts argue the eastern cougar is not a different subspecies from the western cougar and so it’s inaccurate to use the term “extinct”; they’re just not found in the East anymore. But removal from the endangered species list may not be a bad thing; reintroduction will be much less complicated, when it occurs, if there are no recognized endangered cougars present.
A small cougar population remained hidden in the remote backwoods and swamps of southern Florida, and over time became a subspecies that was the exception when declaring the eastern cougar “extinct.” The Department of Interior listed the Florida panther as an endangered subspecies in 1967. The U.S. Fish & Wildlife Service says, “The Florida panther … represents the only known breeding population of puma in the eastern United States.”
Both populations of North American cougar have been somewhat changed by evolution and have become subspecies of Puma concolor. So the much larger population of cougars that once occupied the eastern U.S. and still roams western states is Puma concolor couguar, while the isolated Florida panther is Puma concolor corryi. Other subspecies have also developed in isolated portions of the U.S. and in Central and South America.
While geographical isolation gave rise to the Florida panther, that same insularity now threatens the subspecies survival. Bounded on the north by human presence and habitat alteration, the panther is unable to move northward to reach other cougar populations to breed. The mixing of genes among populations is essential for the long-term stability of the panther population, which is too small to prevent the negative effects of inbreeding, which can ultimately lead to extinction.
This is where the small population of Florida panthers was headed. With lack of contact with other populations, the panther gene pool weakened over time because of inbreeding depression—the buildup of weakened genes—which was expressed in some cats with kinked tails, heart defects, or reproduction problems. The population had dropped to 20-30 individuals by 1995 when the U.S. Fish & Wildlife Service in cooperation with the Florida Fish & Wildlife Conservation Commission introduced eight female Texas cougars (Puma concolor stanleyana), a subspecies closely related to the Florida subspecies and with which the Florida panther had bred before becoming isolated. In 2003, two Texas cougars remained alive in Florida and were removed so that no Texas cougars remain.
With the introduction of gene diversity, the Florida panther population rebounded so that today there are an estimated 100-160 individuals. Still, the population is small and isolated, and it’s not known if a hundred Florida panthers form a minimum viable population that ensures its long-term survival. And so the need for a Florida Wildlife Corridor that would allow the panther to migrate north and reconnect with any eastern cougars still hiding out or western cougars that have wandered east looking for mates and new homes. With free passage of both Florida panthers and western cougars, we could see the reincarnation of an eastern cougar.
Banner photo credit: © Tom Fawls | Dreamstime.com
Free Passage 