Why are wildlife crossings crucial for animals and humans alike?

To create secure pathways for animals to move safely across the landscape, engineered structures and designated zones are constructed over and under roadways. These are wildlife crossings, and they reduce vehicle-animal collisions.

Wildlife crossings are also crucial because they allow animals find food, water, and mates in a larger habitat, which helps prevent isolated populations from becoming genetically distinct or inbred. By maintaining these connections, these nature-mimicking builds support the genetic diversity and the overall health of species.

From the Colorado Department of Transportation in 2021:

“For the past five years, researchers have documented mule deer, elk, black bear, moose, pronghorn, bobcats and many other wildlife species using wildlife underpasses and overpasses on State Highway 9 in Grand County, Colorado.”

The results included “more than 112,000 passages by mule deer over and through the seven crossing structures” during that time, as well as a 90% drop in wildlife-vehicle collisions.

Via National Geographic Education, “the concept was first developed in France in the 1950s.”

“It took off in the Netherlands, where more than 600 crossings have been constructed to protect badgers, elk and other mammals. The Dutch built the world’s longest animal crossing, the Natuurbrug Zanderij Crailoo, an overpass that spans more than 0.8 kilometers (0.5 miles). Wildlife crossings can also be found in Australia, Canada and other parts of the world.”

With six overpasses and 38 underpasses, Canada’s Banff National Park is one of the leading research and monitoring regions for highway wildlife mitigations on the planet.

The 56-mile stretch of Montana’s Highway 93, which traverses the Flathead Indian Reservation, boasts an impressive 42 wildlife crossings, a testament to the Indigenous values upheld by the Confederated Salish and Kootenai tribes.

And in Los Angeles over the 101 freeway, one of the busiest motorways in the United States, the Wallis Annenberg Wildlife Crossing is under construction. Over a decade in the making, the project will expand the range and the genetic pool for local animals, including mule deer, desert cottontails, western toads, coyotes, bobcats, Los Angeles’ famous mountain lions.

Watch construction progress of the Wallis Annenberg Wildlife Crossing via their webcams.

Find more information about the Colorado Department of Transportation research on their website.

Learn more about migration with these videos:
• An annual mule deer migration you have to see to believe
• Decoding the Great Monarch Butterfly Migration
• Tadpoles: The Big Little Migration, a film by Maxwel Hohn
• How do Yellowstone Bison survive harsh winters?
• Thousands of reindeer take an epic journey across Laplandv