The fact that it is a nocturnal creature means that the lion is a symbol 

of authority and command over subconscious thought (as night is an 

ancient symbol of the subconscious - or dream states).

It's interesting that the lion is considered by many ancient cultures to 

be a solar animal symbol, however it is primarily a nocturnal creature, 

conducting its hunting activity mostly at night. Further, the lioness is
considered a lunar animal. 

This serves as a symbolic message of balance and sound judgment. 

In that the lion shares the world of both night and day, the lion bears a 

message of prudence to us.