Timberwolves are generally depicted as similar to their namesake, the grey wolf of North-America and Northern Europe. They are shown as cunning beasts who works in groups to surround and attack their prey. The show portrays them as somewhat fragile, loosing limbs by tripping or hitting something heavy, but they also have the ability to regenerate should they fall apart. It is also stated that they have a stinking breath that make them easy to recognize. This usually also carries over in fan labor. As their entire bodies are made out of wood and leaves, the Timberwolves are usually shown to be afraid of fire.
In the episode Spike At Your Service, the Timberwolves combine themselves into one large being by collecting their wooden parts. This "King Timberwolf" rarely appears in fan fiction, as it was easily defeated by chocking on a rock in the episode, but nevertheless appears as a part of the Timberwolves' arsenal.
Depiction in fan labor
Timberwolves are commonly used as enemies that attacks the main characters when they venture into the Everfree Forest. As they appear to be quite fragile and having regeneration abilities, this allows the characters to fight the wolves without actually killing them, making them easily disposable threats. On the contrary, they can also be shown as surprisingly intelligent and strong creatures, attacking in coordinated packs that surrounds and strategically attacks their victims.
These creatures are often used in "X travels to Equestria" crossover fics, where they are used to show the new characters strength and abilities in combat.