I’ve often wondered why goats have horizontal slit-shaped pupils.

In the little bit of information I’ve been able to find on the subject, animals like goats may have evolved horizontal pupils because better vision in the vertical plane may be beneficial in mountainous environments.  Apparently, having horizontal slit-shaped pupils increases their peripheral depth perception and also makes it easier for them to see at night.

Did you know that donkeys have blind spots directly in front of and behind them and that they can’t see the ground when their heads are raised?