Boar (CR 2)

Medium Animal
Alignment: Always neutral
Initiative: +0; Senses: low-light vision, scent, Listen +7, and Spot +5


AC: 16 (+6 natural), touch 10, flat-footed 16
Hit Dice: 3d8+12 (25 hp)
Fort +6, Ref +3, Will +2
Speed: 40 ft.
Space: 5 ft./5 ft.
Base Attack +2; Grapple +4
Attack: Gore +4 melee
Full Attack: Gore +4 melee
Damage: Gore 1d8+3
Special Attacks/Actions: Ferocity
Abilities: Str 15, Dex 10, Con 17, Int 2, Wis 13, Cha 4
Special Qualities:
Feats: Alertness; Toughness
Skills: Listen +7 and Spot +5
Advancement: 4-5 HD (Medium-size)
Climate/Terrain: Temperate forest
Organization: Solitary
Treasure: none

Source: Monster Manual

Combat

Ferocity (Ex): A boar is such a tenacious combatant that it continues to fight without penalty even while disabled or dying (see page 129 in the Player's Handbook).