“The freeway acts like a fence,” says Miguel Ordeñana. He’s a biologist at the Natural History Museum of Los Angeles. If the area’s cougars don’t have the freedom to roam, experts say, they could die out within 50 years.

That’s why the National Wildlife Federation is building a bridge over Highway 101 called the Wallis Annenberg Wildlife Crossing. It aims to help cougars, deer, foxes, and other creatures move between the two areas.

“The freeway acts like a fence,” says Miguel Ordeñana. He’s a biologist at the Natural History Museum of Los Angeles. Experts say these cougars need freedom to roam. Without it, they could die out within 50 years.  

So the National Wildlife Federation is building a bridge over Highway 101. It’s called the Wallis Annenberg Wildlife Crossing. It will help animals move between the two areas. Cougars, deer, foxes, and other creatures will use it.

When animals try to cross busy roads, the results are often tragic. About 1 million to 2 million crashes occur between vehicles and wildlife each year in the U.S. The accidents can be deadly for both animals and people.

Wildlife stuck in small areas can struggle to find food. Some animals, like cougars, need space to roam. Male cougars may kill each other if they are restricted to a small territory, says Ordeñana.

Over time, isolated groups of animals tend to become unhealthy. The cougars living south of Highway 101 are all close relatives. When closely related animals breed, their offspring are more likely to have health problems.

So animals try to cross busy roads. Often, the results are deadly. A vehicle may crash into the animal. This happens about 1 million to 2 million times each year in the U.S. The accidents can kill both animals and people.

Wildlife in small areas can struggle to find food. Some animals, like cougars, need space to roam. Male cougars shouldn’t be together in a small territory. They may kill each other, says Ordeñana.

Groups of animals in small areas face another problem. Over time, they tend to become unhealthy. The cougars south of Highway 101 are all close relatives. When closely related animals breed, their offspring may have health problems.

Conservationists have built thousands of wildlife crossings. To decide where to build them, researchers study where animals are most often hit by vehicles. They also use the Global Positioning System, or GPS, to track where animals travel.

The design of a crossing depends on its location and the animals using it. Animals are more likely to use paths that resemble their habitats. Bridges are usually covered with local soils and plants. Tunnels under roads are often made to mimic streams.

The Wallis Annenberg Wildlife Crossing will be covered with local trees and flowers. It will also have walls to quiet the noise from highway traffic. Builders expect to finish the bridge in 2025. Then scientists will use cameras to study how animals use it. “The people of Los Angeles are not giving up on their wildlife,” says Ordeñana.

Conservationists have built thousands of wildlife crossings. Researchers must decide where to build them. So they find out where vehicles hit animals most often. They also track animals’ paths with the Global Positioning System, or GPS.

How is a crossing designed? That depends on its location and the animals using it. Paths are made to look like animals’ habitats. Then animals are more likely to use them. Bridges are usually covered with local soils and plants. Tunnels are built under roads. They are made to look like streams.

Local trees and flowers will cover the Wallis Annenberg Wildlife Crossing. It will also have walls. That will quiet the noise from highway traffic. Builders expect to finish the bridge in 2025. Then scientists will set up cameras. They’ll study how animals use the crossing. “The people of Los Angeles are not giving up on their wildlife,” says Ordeñana.