List of wild animals found throughout Skyrim that will attack you on sight
Bear - Bears will not attack you on sight, but if you get within a certain range (which is quite far) they will charge you. There are 3 variants of bears.
Horker - As with the beat, will not attack immediately, you are able to get much closer without being attacked than with bears.
Ice Wraith - Not exactly an animal, but Skyrim classifies them as one. Difficult to hit with arrows, melee weapons are recommended. Shield bashing will stagger them so they are easier to hit.
Mudcrab - Extremely easy enemies to kill. No strategy required, even for lower levels.
Skeever - Attacks aggressively, but their attacks are so weak that one or two sword swipes will dispatch them.
Slaughterfish - Rare to fight, sometimes found in rivers, easy to defeat.
Sabre Cat - Aggressive attacker, relatively low health, 2 variants.
Wolf - Travels in packs which attack any prey as a group