The Iron Curtain has been down for quite some time, but things haven't changed for everybody.

For years the Iron Curtain (actually, a fence) separated two populations of red deer living in the forests encompassing the border between Germany and what is now the Czech Republic. When government officials began to dismantle the fence in 1989 (around the time the Berlin Wall fell), the physical barrier between those populations was removed. But when wildlife biologists began studying the deer in 2002, they quickly realized that the deer living in Germany were not migrating into the Czech Republic, and the deer living in the Czech Republic were not migrating into Germany. In other words, both populations of deer were still behaving as if the fence remained intact.

One deer in particular has become a microcosm of the entire population. Her name is Ahornia, and her movements in the forests of eastern Germany were tracked for several years by a GPS collar fitted to her neck by biologist Marco Heurich. During the time she was monitored, Ahornia's location was tracked more than 11,000 times in Germany—but not a single time in the Czech Republic. She was tracked at the border of the two countries several times, but she never crossed over.

Two elements of Ahornia's story are particularly noteworthy. First, she was born 18 years after the destruction of the Berlin Wall and the fence that comprised the Iron Curtain. She has no physical memory of the fence's existence, and yet she is still blocked by it. Second, the land formerly occupied by the fence and its guard towers has now been turned into a large and thriving nature preserve. In other words, the land beyond the fence has become a haven—the perfect home for deer like Ahornia and her family—and yet she will not enter.

Marco Heurich and his team of biologists have come up with several explanations for the deer's strange behavior. Most deer travel across traditional trails, for example—ones that are passed down through generations by modeling and repetition. It's possible that Ahornia and the other members of her herd simply haven't ventured beyond the beaten path.

But wildlife filmmaker Tom Synnatzschke, who often works in the area, has a different explanation. According to Tom, "The wall in the head is still there."

This illustration was first heard in a sermon by Walt Barrett at Riverside Community Church in St. Charles, Illinois.