Several panthers, however, have been documented north of the Caloosahatchee since the early 19 70s. In 1973 working for the World Wildlife Fund, professional cougar hunter Roy McBride and his dogs treed an aged female panther in the Fisheating Creek area. In the mid-1980s Game Commission biologist Jayde Roof conducted sign surveys for panthers at Fisheating Creek as well as at Corkscrew Swamp Sanctuary in Collier County. Crossing fragmented habitat is very dangerous for panthers. Collisions with vehicles have been a significant cause of panther deaths , although construction of wildlife underpasses along I-75 and SR 29 has decreased these accidents.
Habitat quality affects use of underpasses.
East of state road 29, panthers rarely use the I-75 underpasses. Biologists did find tracks of an uncollared male crossing an underpass about 5 miles east of SR 29. Biologist Darrell Land thinks this lack of use of the underpasses east of SR 29 is related to the poorer quality habitats to the east that discourage panther use. Roads also open up areas to human development and activities that may further contribute to habitat loss and to disruption of panthers' normal behavior.