Monster Manual
Keen Hearing and Smell. The wolf has advantage on Wisdom (Perception) checks that rely on hearing or smell. Pack Tactics. The wolf has advantage on an attack roll against a creature if at least one of the wolf's allies is within 1 square of the creature and the ally isn't incapacitated.
Bite. Melee Weapon Attack: +4 to hit, reach 1 sq., one target. Hit: 7 (2d4 + 2) piercing damage. If the target is a creature, it must succeed on a DC 11 Strength saving throw or be knocked prone.