A quick search on the forums did not produce any results on the subject, so I shall suggest my idea.
I know a lot of people have had problems with those damn ninja boars/bears. I think there should be some warning sign when an aggressive animal is nearby. Possibly a Metal Gear Solid-esque ! above your head, or something to that extent. It doesn't necessarily have to show you where the animal is, but just something to say "Hey! Dumbfuck! Watch out for that bear!"
For any who say that this isn't realistic, think about it. Could you not hear a bear panting, snapping twigs, grunting, etc? Same goes for boars too.
The range in which you can detect animals from should increase with perc, but should be limited to about the default client screen size, because nobody wants to have 30 !'s above your head that have animals that are 3 minimaps away.
Comment, Crticize, Add to the idea. Grab those thinking caps.