Dire Wolverine (CR 4)

Large Animal
Alignment: Always neutral
Initiative: +3 (Dex); Senses: low-light vision, scent, Listen +7, and Spot +7

AC: 16 (-1 size, +3 Dex, +4 natural), touch 12, flat-footed 13
Hit Dice: 5d8+23 (45 hp)
Fort +8, Ref +7, Will +5
Speed: 30 ft., climb 10 ft.
Space: 10 ft./5 ft.
Base Attack +3; Grapple +13
Attack: Claw +8 melee
Full Attack: 2 claws +8 melee and bite +3 melee
Damage: Claw 1d6+6, bite 1d8+3
Special Attacks/Actions: Rage
Abilities: Str 22, Dex 17, Con 19, Int 2, Wis 12, Cha 10
Special Qualities:
Feats: Alertness; Toughness; Track
Skills: Climb +14, Listen +7, and Spot +7
Advancement: 6-15 HD (Large)
Climate/Terrain: Cold forest
Organization: Solitary or pair
Treasure/Possessions: None

Source: Monster Manual

Rage (Ex): A dire wolverine that takes damage in combat flies into a berserk rage on its next turn, clawing and biting madly until either it or its opponent is dead. An enraged dire wolverine gains +4 Strength, +4 Constitution, and -2 AC. The creature cannot end its rage voluntarily.

Dire wolverines attack opponents wantonly, fearing no other creatures.