Why do deers run into glass windows?



I’ve been seeing it happen more and more. Deers will randomly charge through a window/glass pane (sometimes a house, sometimes at a mall, sometimes at a store) and I have no clue why

In: Biology

The simple answer would be, they cannot see the glass, have never experienced glass and thus don’t think there is a barrier before them.

A clean pane of glass is transparent and therefore very indistinguishable from empty air. You even see people walk streight into glass doors from time to time. There is a couple of things making this more common for deers. Firstly a deer in an urban environment is often very scared and wants to flee the situation. And while running full speed in a panic it can be hard to notice a glass pane. Secondly deer and a lot of other herbivores have very bad depth perception due to how their eyes are located. This means that they are unable to notice how far away the dust and grime on the glass is and can interpret it as being further away then it really it.