Is there a duration to an Ogre Mage's change shape ability?

[eyebreaker7]

Change Shape (Su)
An ogre mage can assume the form of any Small, Medium, or Large humanoid or giant.

It doesn't say anything in the description for the ogre mage.

[Doctor Despair]

There is reference text for that special ability, however. Let's take a look:

A creature with this special quality has the ability to assume the appearance of a specific creature or type of creature (usually a humanoid), but retains most of its own physical qualities. A true seeing spell or ability reveals the creature’s natural form. A creature using change shape reverts to its natural form when killed, but separated body parts retain their shape. A creature cannot use change shape to take the form of a creature with a template. Changing shape results in the following changes to the creature:


The creature retains the type and subtype of its original form. It gains the size of its new form.
The creature loses the natural weapons and movement modes of its original form, as well as any extraordinary special attacks of its original form not derived from class levels (such as the barbarian’s rage class feature).
The creature gains the natural weapons, movement modes, and extraordinary special attacks of its new form.
The creature retains all other special attacks and qualities of its original form, except for breath weapons and gaze attacks.
The creature retains the ability scores of its original form.
Except as described elsewhere, the creature retains all other game statistics of its original form, including (but not necessarily limited to) HD, hit points, skill ranks, feats, base attack bonus, and base save bonuses.
The creature retains any spellcasting ability it had in its original form, although it must be able to speak intelligibly to cast spells with verbal components and it must have humanlike hands to cast spells with somatic components.
The creature is effectively camouflaged as a creature of its new form, and gains a +10 bonus on Disguise checks if it uses this ability to create a disguise.
Any gear worn or carried by the creature that can’t be worn or carried in its new form instead falls to the ground in its space. If the creature changes size, any gear it wears or carries that can be worn or carried in its new form changes size to match the new size. (Nonhumanoid-shaped creatures can’t wear armor designed for humanoid-shaped creatures, and viceversa.) Gear returns to normal size if dropped.



The referenced ability has no mention of duration. Let's check the reference text for supernatural abilities to see if there's any standard duration. I'm actually interested in this one, because I was recently commenting on the Evangelist's Convert the Unfaithful ability for the same reason: no listed duration seems to suggest it's permanent. Let's take a look:

Supernatural abilities are magical and go away in an antimagic field but are not subject to spell resistance, counterspells, or to being dispelled by dispel magic. Using a supernatural ability is a standard action unless noted otherwise. Supernatural abilities may have a use limit or be usable at will, just like spell-like abilities. However, supernatural abilities do not provoke attacks of opportunity and never require Concentration checks. Unless otherwise noted, a supernatural ability has an effective caster level equal to the creature’s Hit Dice. The saving throw (if any) against a supernatural ability is:

10 + ½ the creature’s HD + the creature’s ability modifier (usually Charisma).

It has a standard use-time and a standard saving throw (in this case irrelevant), but no standard duration.

I think you're good; it should be usable at-will and for an unlimited duration, but take a standard action to use.

[Venger]

That is the answer. They stay in that shape as long as they like.