Crews on Friday broke ground on a wildlife crossing over the 101 Freeway in Agoura Hills that is meant to provide mountain lions and other animals a safe route to the Santa Monica Mountains.

Billed as the world’s largest wildlife crossing, the bridge will stretch 200 feet over 10 lanes of the busy freeway.

The hope is that the bridge will provide more room to roam for animals stifled by urban development, including big cats, coyotes, deer, lizards, snakes and other creatures.

And most notably, the crossing would help mountain lions escape extinction by providing them safe passage to food and mates, the National Wildlife Federation says.

Residents and local officials were gathered at King Gillette Ranch Friday to celebrate the groundbreaking. The freeway’s on-ramps and off-ramps were closed to traffic at Liberty Canyon and Agoura roads until 2 p.m. for the ceremony.

The need for the Wallis Annenberg Wildlife Crossing was supported by research from National Park Service biologists, who have been studying wildlife in the Santa Monica Mountains since 1996.

“The new crossing will re-connect an entire ecosystem that has long been fragmented by an almost impenetrable barrier for wildlife,” officials from the Santa Monica Mountains said.

Biologists say it was always clear that the 101 Freeway was a major barrier for the movement of wildlife in the Santa Monica Mountains National Recreation Area, which is home to more than 450 animal species.

Isolation by roads and urban developments has been the biggest conservation challenge facing wildlife in the area, NPS said.

The barrier effect even extended to gene flow, with significant genetic effects seen in mountain lions, according to NPS researchers.

Biologists have already begun seeing the physical effects of low genetic diversity on the animals, including noticing kinks at the end of their tails.

“This crossing is timely, considering our recent discovery of the first physical signs of inbreeding depression occurring in our isolated mountain lion population in the Santa Monica Mountains,” said Jeff Sikich, the lead field researcher on the mountain lion study. “Habitat fragmentation is the key challenge wildlife is facing here.” 

While studies have found that roadways are largely confining mountain lions in the mountains, some have been killed trying to cross freeways.

Just one day before the groundbreaking on the wildlife crossing, an 18-month-old mountain lion was struck and killed on the 405 Freeway in the Brentwood area.

The cougar, P-97, was the 26th mountain lion to be killed by a vehicle since the study began about two decades ago, according to officials from the Santa Monica Mountains.