Border Control

How national borders become natural borders.

Dan Kitwood/Getty Images
Dan Kitwood/Getty Images
Dan Kitwood/Getty Images

Field mice may not carry passports, and nobody ever asked a tree frog for a green card, but do animals care about imaginary lines on a map? In fact, national borders can become natural borders over time, with significant consequences for the nonhumans living on either side.     

After Israel normalized relations with its neighbor Jordan in 1994, University of Haifa biologist Uri Shanas studied how the fauna on either side of the border differed. He found that rodents in Israel were much more cautious than their counterparts in Jordan -- a distinction Shanas attributes to Israel's more modern agricultural development.     

Such differences can persist for decades. Scientists have observed that red deer in the forests on the Czech-German border are still stuck in the Cold War, avoiding the old boundary because a long-dismantled electric fence once ran along it. But the effect isn't always negative. The 390-square-mile demilitarized zone between North and South Korea has been a no-go area for humans for decades, which makes it a great place for rare red-crowned cranes and Chinese water deer. Now there is talk of making the de facto wildlife preserve permanent: a very rare case of animals benefiting from human conflict. 

Field mice may not carry passports, and nobody ever asked a tree frog for a green card, but do animals care about imaginary lines on a map? In fact, national borders can become natural borders over time, with significant consequences for the nonhumans living on either side.     

After Israel normalized relations with its neighbor Jordan in 1994, University of Haifa biologist Uri Shanas studied how the fauna on either side of the border differed. He found that rodents in Israel were much more cautious than their counterparts in Jordan — a distinction Shanas attributes to Israel’s more modern agricultural development.     

Such differences can persist for decades. Scientists have observed that red deer in the forests on the Czech-German border are still stuck in the Cold War, avoiding the old boundary because a long-dismantled electric fence once ran along it. But the effect isn’t always negative. The 390-square-mile demilitarized zone between North and South Korea has been a no-go area for humans for decades, which makes it a great place for rare red-crowned cranes and Chinese water deer. Now there is talk of making the de facto wildlife preserve permanent: a very rare case of animals benefiting from human conflict. 

 

Israel/Jordan
Border: Largely fenced
Animals affected: Gerbils and red foxes

 

Germany/Czech Republic
Border: Open and unfenced since 1989
Animals affected: Red deer

 

U.S./Mexico
Border: Nearly a third fenced
Animals affected:  Jaguars and ocelots

 

North Korea/South Korea
Border: Patrolled on both sides by nearly 2 million troops
Animals affected:  Red-crowned cranes, Chinese water deer, spotted seals, and lynx, among others
Joshua E. Keating was an associate editor at Foreign Policy.

More from Foreign Policy

An illustration shows George Kennan, the father of Cold War containment strategy.
An illustration shows George Kennan, the father of Cold War containment strategy.

Is Cold War Inevitable?

A new biography of George Kennan, the father of containment, raises questions about whether the old Cold War—and the emerging one with China—could have been avoided.

U.S. President Joe Biden speaks on the DISCLOSE Act.
U.S. President Joe Biden speaks on the DISCLOSE Act.

So You Want to Buy an Ambassadorship

The United States is the only Western government that routinely rewards mega-donors with top diplomatic posts.

Chinese President Xi jinping  toasts the guests during a banquet marking the 70th anniversary of the founding of the People's Republic of China on September 30, 2019 in Beijing, China.
Chinese President Xi jinping toasts the guests during a banquet marking the 70th anniversary of the founding of the People's Republic of China on September 30, 2019 in Beijing, China.

Can China Pull Off Its Charm Offensive?

Why Beijing’s foreign-policy reset will—or won’t—work out.

Turkish Defense Minister Hulusi Akar chairs a meeting in Ankara, Turkey on Nov. 21, 2022.
Turkish Defense Minister Hulusi Akar chairs a meeting in Ankara, Turkey on Nov. 21, 2022.

Turkey’s Problem Isn’t Sweden. It’s the United States.

Erdogan has focused on Stockholm’s stance toward Kurdish exile groups, but Ankara’s real demand is the end of U.S. support for Kurds in Syria.