For creatures with spell-like abilities, a designated caster level defines how difficult it is to dispel their spell-like effects and to define any level-dependent variables (such as range and duration) the abilities might have. The creature’s caster level never affects which spell-like abilities the creature has; sometimes the given caster level is lower than the level a spellcasting character would need to cast the spell of the same name. If no caster level is specified, the caster level is equal to the creature’s Hit Dice. The saving throw (if any) against a spell-like ability is:
10 + the level of the spell the ability resembles or duplicates + the creature’s Cha modifier.