Dire Wolf (CR 3)

Large Animal
Alignment: Always neutral
Initiative: +2 (Dex); Senses: low-light vision, scent, Listen +7, and Spot +7

AC: 14 (-1 size, +2 Dex, +3 natural), touch 11, flat-footed 12
Hit Dice: 6d8+18 (45 hp)
Fort +8, Ref +7, Will +6
Speed: 50 ft.
Space: 10 ft./5 ft.
Base Attack +4; Grapple +15
Attack: Bite +11 melee
Full Attack: Bite +11 melee
Damage: Bite 1d8+10
Special Attacks/Actions: Trip
Abilities: Str 25, Dex 15, Con 17, Int 2, Wis 12, Cha 10
Special Qualities:
Feats: Alertness; Run; Track; Weapon Focus (bite)
Skills: Hide +0, Listen +7, Move Silently +4, Spot +7, and Survival +2*
Advancement: 7-18 HD (Large)
Climate/Terrain: Temperate forests
Organization: Solitary or pack (5-8)
Treasure/Possessions: None

Source: Monster Manual

Trip (Ex): A dire wolf that hits with a bite attack can attempt to trip the opponent as a free action (see page 139 in the Player's Handbook) without making a touch attack or provoking an attack of opportunity. If the attempt fails, the opponent cannot react to trip the dire wolf.

Skills: A dire wolf receives a +1 racial bonus to Listen, Move Silently, and Spot checks and a +2 racial bonus to Hide checks. It also receives a +4 racial bonus to Survival checks when tracking by scent.

Dire wolves prefer to attack in packs, surrounding and flanking the foe when they can.