According to the Wall Street Journal, red deer living in West Germany refuse to cross the border into the Czech Republic because there used to be an electric fence along the border between the two nations. This migration pattern is occuring now despite the fact that there is no fence or physical barrier separating the two nations, only a walking path as the entire border is a nature preserve, and the red deer alive during the Cold War are not even the same ones alive today. However, as the Journal explains:
“In the past, the deer didn’t go to the Czech side because of the fence,” says Marco Heurich, a wildlife biologist who runs the animal tracking project in the Bavarian Forest National Park in Germany. “Now the fence is gone but they still stop at the border.”
One reason, he says, is that deer have traditional trails, passed on through the generations, with a collective memory that their grounds end at the erstwhile barrier. Females, who stay with their mothers longer than males and spend more time absorbing their mothers’ movements, stick even more closely to the traditional turf.
Even for animals, there is an impact from the loss of freedom.