Gullo said rangers have reported seeing a mountain lion this past winter. The undercrossing was built in 2006 beneath busy Harbor Boulevard and stretches 160 feet long, stands 17 feet high and 20 feet wide. It links 4,600 acres of publicly protected land to the west with 14,000 acres to the east, strengthening the biodiversity of animals that use it, according to a 2008 study by David Elliott and Paul Stapp of the Department of Biological Science at Cal State Fullerton. On a recent sunny morning, along the eastern edge of the Puente-Chino Hills, Mariscal and Andrea Gullo, executive director of the Puente Hills Habitat Preservation Authority, checked for wildlife tracks within the tubular Harbor Boulevard Wildlife Underpass. “We are just good at killing them in Southern California with cars, poaching and permitted killings,” he said. “The mortality rates are high,” said Winston Vickers, an associate veterinarian from UC Davis who studies mountain lions. The group hopes to have the massive animal bridge completed by 2023.

Of that, $8.4 million has been raised by the #SaveLACougars campaign. The Santa Monica Mountains overpass would carry animals over 10 lanes of the 101 Freeway and would cost a whopping $60 million. Likewise, an overpass and two underpasses are being considered to help stranded mountain lions in the Santa Ana Mountains cross the 15 Freeway and connect with a larger population in the Palomar Mountains south of the Temecula Creek Bridge in Riverside County. It’s a concept that is decades in the making. The Nature Conservancy and UC Davis have suggested a wildlife overpass at the Liberty Canyon Road exit of the 101 Freeway in Agoura Hills that would connect stranded mountain lions in the Santa Monica Mountains with a wider population in the Simi Hills and Santa Susana Mountains. Once thought of as ridiculous or too expensive, these wildlife overpasses and undercrossings allow animals to get where they’re going and curtail inbreeding, genetic demise, roadway collisions and the chance of being eliminated from the planet forever. Not for humans, not for automobiles but for the wild things that live among us. Call it a different kind of alternative transportation.

Animal overpass