Animals’ natural habitats are shrinking, and the spaces they have left are often carved up by dangerous, multi-lane highways. Highways fracture ecosystems into isolated parts, which can limit genetic diversity of the organisms in each portion and jeopardize a species’ chance of survival. When animals attempt to cross these barriers, they end up putting themselves in harm’s way, and depending on their size, they can threaten the safety of people on the road.

A solution that’s gaining popularity around the world is the construction of animal crossings. Also known as animal bridges or wildlife overpasses, these structures extend over busy highways like normal bridges, but instead of cars, they provide safe passage to wildlife. Greenery planted over bridges can make them inviting places for wildlife, and fences along roads sometimes funnel animals toward the safe crossing points. Different types of bridges have been built to cater to different animals: There’s an animal crossing for crabs in Australia and one for squirrels in Washington state. Check out these and more examples of extraordinary animal crossings around the world below.

1. Wildlife Overpass // Banff National Park, Canada

Lucilleb/iStock via Getty Images

Banff National Park in Alberta, Canada, is home to megafauna like moose, elk, and grizzly bears. When these animals attempt to cross a highway, they pose a threat to human drivers and passengers as well as themselves. That’s why, beginning in 1996, officials installed six wildlife overpasses and 38 underpasses on the Trans-Canada Highway, which bears 30,000 vehicles along the 25-mile stretch from Banff National Park to the Kananaskis River every day. Wildlife mortality in the area has dropped by 80 percent as a result of the animal crossings.

2. Crab Bridge // Christmas Island National Park, Australia


View this post on Instagram

A post shared by Chris Bray Photography (@chrisbrayphotography) on

Large animals like elk and bears aren’t the only ones that deserve safe passage across busy streets. Each year, 50 million red crabs on Australia’s Christmas Island head toward the sea to spawn—a mass migration that’s been complicated by human development in recent years. To help the crustaceans reach their destination safely, the island built a 16-foot-high bridge the crabs can scale to cross a busy road. Thirty-one special crab underpasses and 65 miles of plastic barriers funneling them toward the passageways were also installed.

3. Natuurbrug Zanderij Crailoo // The Netherlands


View this post on Instagram

A post shared by DesignforMotion (@designformotion) on

Natuurbrug Zanderij Crailoo

in The Netherlands is the longest wildlife crossing on Earth. The 2625-foot-long, 164-foot-wide bridge stretches across roads, railways, and a sports complex. Animals like deer, wild boar, and European badgers use it to travel to isolated environments that would otherwise be inaccessible to them. Natuurbrug Zanderij Crailoo translates to “sand quarry natural bridge,” and it's one of more than 600 "ecoducts" in the nation.

4. Nutty Narrows Bridge // Longview, Washington

Bruce Fingerhood, Flickr // CC BY-NC 2.0

Animal crossings come in all shapes and sizes. Nutty Narrows Bridge in Longview, Washington, is suspended above a busy thoroughfare and it’s just wide enough to fit a squirrel scampering to safety. Local builder Amos Peters constructed it in 1963 to keep squirrels away from the traffic below. Since then, several similar squirrel bridges have been installed around town.

5. A556 Green Bridge // United Kingdom

Overpasses that allow wildlife to avoid traffic are called “green bridges” in the UK. In 2018, one of these bridges opened above the Knutsford-Bowdon bypass on A556 in Cheshire, England. The greenery is meant to attract small animals like badgers and voles. Unlike some other wildlife crossings, this one is open to people as well. A path on the bridge aids agricultural workers crossing the highway.

6. Wildlife Overpass // Snoqualmie Pass, Washington

Washington State Department of Transportation, Flickr // CC BY-NC-ND 2.0

Even before the construction of a wildlife bridge near Snoqualmie Pass in Washington was completed, it was attracting animals. Deer were spotted using the overpass to cross Interstate 90 as early as 2018. After 8-foot walls were erected around the bridge to muffle noise and local flora was planted, the animal crossing official opened in 2019. It was designed to play host to elk, bears, and mountain goats, but some unexpected visitors have also been spied using the bridge. It was the site of an alleged Bigfoot sighting earlier in 2020.

7. Eco-link @ BKE // Singapore

Jnzl's Photos, Flickr // CC BY 2.0

When you hear the word Singapore, you may picture a futuristic metropolis, but the island is home to plenty of wildlife as well as people. Two rainforest nature reserves outside the city center were separated by traffic for three decades before a wildlife overpass linked them together in 2013. Singapore's Eco-Link @ BKE spans eight lanes and it was the first wildlife overpass of its kind built in Southeast Asia.