LOS ANGELES (CNS) — A mountain lion was fatally struck by a vehicle Thursday on the San Diego (405) Freeway in the Brentwood area, highlighting the dangers facing the big cats living amid a maze of freeways and the reasoning behind a major wildlife crossing that will break ground Friday.

Officers from the California Highway Patrol received a call just before 1 a.m about an animal lying on the southbound 405 Freeway south of Getty Center Drive exit. Officers briefly closed the freeway to move the cat out of freeway lanes.

According to Ana Cholo of the National Park Service, the lion was determined to be an 18-month-old male known as P-97. The lion was first spotted on trail cameras in the Santa Monica Mountains in the winter of 2020, when he was estimated to be about three months old.

According to the NPS, P-97 had recently separated from his mother, known as P-54, and was tracked by GPS near the area where he was killed Thursday. NPS officials said the lion was likely looking "for a territory to call his own."

The NPS has been studying the movement of lions in the Santa Monica Mountains for the past 20 years, tracking roughly 100 of the cats.

P-97's death came one day before a groundbreaking ceremony for the Wallis Annenberg Wildlife Crossing, which will span the 101 Freeway in Liberty Canyon near Agoura Hills. The $85 million project will be the largest crossing of its kind in the world — a fully landscaped passage for wildlife that will stretch 210 feet over 10 lanes of highway and pavement.

The Wildlife Crossing is being developed following 20 years of studies from the National Park Service that found roads and urban development are deadly for animals trying to navigate the Los Angeles area. Urban development has also created islands of habitats that can genetically isolate the region's animals.

Researchers have estimated that the mountain lion population in the Santa Monica Mountains could become extinct within 50 years without an influx of genetic diversity. The lions are largely isolated due to freeways that act as barriers to movement across the region. The crossing aims to provide a connection between the small population of mountain lions in the Santa Monica Mountains and the larger and genetically diverse populations to the north.

"This week was supposed to be one of celebration as we mark the groundbreaking of a wildlife bridge in Agoura Hills. Instead, we're saddened by the violent death of yet another mountain lion," J.P. Rose, a senior attorney at the Center for Biological Diversity, said in a statement. "These tragedies are preventable if California invested in more wildlife crossings, which protect both wildlife and people from dangerous collisions. I hope our leaders in Sacramento take a serious look at the Safe Roads and Wildlife Protection Act, a sensible piece of legislation that will bring more wildlife crossings to the state."

The proposed legislation would require state officials to identify "roadkill hotspots" and construct at least 10 wildlife crossings per year on state roads.