UPDATE: Saving Mountain Lions – The World’s Largest Wildlife Crossing
Following WAN’s recent coverage of the Wallis Annenberg Wildlife Crossing, the world’s largest overpass for wildlife spanning a major freeway in Agoura Hills, CA, many have asked how mountain lions and other species will navigate the crossing, whether they’ll still face the risk of vehicle collisions, and why public tours are being offered before it officially opens.
Last year, Katie Cleary from World Animal News interviewed the newly elected mayor of Agoura Hills, Jeremy Wolf, about this groundbreaking project. Strategically located to reconnect critical habitats separated by California’s 101 Freeway, the crossing is crucial for the survival of mountain lions in the Santa Monica Mountains. These apex predators face extinction threats due to isolation and inbreeding. By linking fragmented habitats, the crossing aims to restore the genetic diversity vital for their survival.
Mountain lions, also known as cougars or pumas, are apex predators that play a vital role in maintaining the biodiversity of the Santa Monica Mountains. However, urban expansion and highways have severely fragmented their habitats, creating isolated populations with limited gene flow. This isolation increases the risk of genetic disorders and puts them on the brink of extinction in this biodiversity hotspot.
This project is not just symbolic, it’s lifesaving. Far too many wild animals have been killed attempting to cross the 101 Freeway. The Wallis Annenberg Wildlife Crossing provides a safe passage not only for mountain lions, but also for deer, bobcats, bats, desert cottontails, and countless other species.
The construction showcases cutting-edge eco-design and conservation engineering. Approximately 6,000 cubic yards of specially engineered soil, composed of sand, silt, clay, compost, and local mycorrhizal fungi, has been spread across the crossing, which spans ten lanes of traffic. Vegetation grown from locally sourced seeds will transform the bridge into a living landscape that connects to the Santa Monica Mountains on both sides of the freeway.
About 5,000 native shrubs, grasses, and perennials will be planted, featuring coastal sage scrub and other flora native to the region. This is part of a broader restoration effort including 12 acres of open space and 50,000 native plants.
Last year’s soil placement ceremony highlighted the collaborative efforts of government officials, scientists, and conservationists. Among those in attendance were Mayor Penny Sylvester, former Senator Fran Pavley, newly elected Mayor Jeremy Wolf, and numerous environmental advocates dedicated to protecting wildlife and natural habitats.
Currently, expert-led tours and educational previews allow the public to view the project from designated areas such as guided hikes and observation points. The crossing itself will not be open to the public, its trails and landscaping are designed exclusively for wildlife. Visitors can watch from nearby trails or viewing platforms but cannot walk across it.
Timeline: Construction is expected to finish by late 2026. Tours will continue after the official opening.
The Wallis Annenberg Wildlife Crossing represents a bold step forward in conservation, combining animal welfare, science, and community collaboration. It stands as a model for other regions, showing that with vision and determination, humans and wildlife can coexist safely.
Tour reservations and additional information are available HERE!
