Why did the chichen cross the road?We may never know,since she probably never got to the other side,In the US alone,about a million animals are flattened by passing motorists each day-and that doesn't count all the bugs!Animals are constantly confronted with barriers,some of them completely natural,and others that we build that are barely barriers at all.
As we build our own infrastructure,we're also adding to this obstacle course without meaning to,and these unintentional fences are some of the most effective animal barriers out there.Roads are just the beginning.Take high-tension power lines,for example.They may look harmless to us,but many other creatures steer clear.
We can't say why for sure,but these animals' ultraviolet vision may mean that the UV flashes discharging from the cables make for a very scary sight.And even weirder stuff can get in animals way.Many hoofed mammals are hesitant to cross linear features ,like clear-cut corridors,pipelines-even rows of rocks or painted lines on the ground-leaving them psychologically stranded on one side or the other.
While one stranded cow might not be a huge problem,if enough animals become isolated from food,mates,and protection,entire populations can dwindle and even disappear.One solution would be to get rid of all these obstacles,but we aren't likely to give up roads,power,or pipelines any time soon.
And even when we remove physical barriers,their stopping power can stick around.The "Iron Curtain"between the Czech Republic and Germany was torn down more than 20 years ago,but red deer still won't corss that divide.Generations of fawns learned to avoid the barbed wire fence,and even with it gone,the lessons live on.
而且即使我们移除了物理障碍 阻滞力依然存在,捷克共和国和德国之间的"铁幕",撤除已有20多年了,但是赤鹿(马鹿)依然不会穿过这条分水岭,一代代的小鹿学会了避开那道倒刺铁丝围栏,即使现在它消失了 经验教训依然还在.
Luckily,a little ingenuity goes a long way in guiding animals over,under,or around the obstacies we put in their way.Just as a footbridge helps us cross dangerous roads,we can build overpasses that help deer,monkeys,and crabs do the same.Elephants go underneath,and we've even engineered salmon cannons to help fish sail past dams on their way upriver.
We can bridge mental barriers too,encouraging animals to cross obstacles that could otherwise psych them out.In the end,even if we don't know why the chicken crossed the road,at least we can help her get there safely.