Perhaps like some goats in caricature they have the ability to "eat anything", which they use to chew through tomb doors and into graves in order to devour the interned? Since it says they're ghouls, one presumes they eat the dead.
I like this idea. Take one ravenous living creature and combine with a ravenous undead and fun ensues!
Here are the 3e stats for a goat...
Mountain Goat
Small Animal
Hit Dice: 1d8+2 (6 hp)
Initiative: +1
Speed: 40 ft. (8 squares)
Armor Class: 14 (+1 size, +1 Dex, +2 natural), touch 12, flat-footed 13
Base Attack/Grapple: +0/-4
Attack: Horns +1 melee (1d6)
Full Attack: Horns +1 melee (1d6)
Space/Reach: 5 ft./5 ft.
Special Attacks: Stampede
Special Qualities: Low-light vision
Saves: Fort +4, Ref +3, Will -1
Abilities: Str 10, Dex 12, Con 15, Int 2, Wis 8, Cha 4
Skills: Listen +5, Spot +5
Feats: Weapon Finesse
Environment: Any mountains
Organization: Herd (2-16)
Challenge Rating: ¼
Treasure: None
Alignment: Always neutral
Advancement: -
Level Adjustment: -
A typical mountain goat stands 3 feet tall at the shoulders.
Combat
Stampede (Ex): A herd of mountain goats can stampede. A creature caught in the stampede must make a DC 12 Dexterity check or suffer 2d6 points of nonlethal damage from being bowled over and trodden upon by the animals.
Source: Dungeon Magazine #83, p. 70.