DC to identify critter

[Selgard]

Knowledge Check to Identify a Critter:

Spoiler:

You can use this skill to identify monsters and their special powers or vulnerabilities. In general, the DC of such a check equals 10 + the monster's CR. For common monsters, such as goblins, the DC of this check equals 5 + the monster's CR. For particularly rare monsters, such as the tarrasque, the DC of this check equals 15 + the monster's CR, or more. A successful check allows you to remember a bit of useful information about that monster. For every 5 points by which your check result exceeds the DC, you recall another piece of useful information. Many of the Knowledge skills have specific uses as noted on Table: Knowledge Skill DCs.

Silvanshee Agathion:

Spoiler:

Silvanshee CR 2

Silvanshee Agathion:

Spoiler:

This black cat has gray stripes, violet eyes, and an unusual white blaze on its chest. (and) A silvanshee is the size of a large domestic cat, though almost always sleek rather than fat, and weighs 20 pounds on average.

So the question.
By RAW the DC to identify this creature is either 7, 12, or 17 depending on the DM's assessment of how common the critter is.

So, the advice.
Should the physical description of the creature alter this in anyway?
I mean, by the words given: this cat looks like.. a cat. No glowing runes, no opposable thumb, no weird eyes, no extra appendages.. Its just a cat.
Should the PC (or an opponent for that matter) be able to make a relatively low DC to determine that this beast who looks just like any other cat in the world is actually not a cat?
This is, of course, assuming they don't witness the cat doing something un-catlike.. such as fly or talk or blow off a channel energy or something.

If two cats are standing side by side and one is a Silvanshee, then by the RAW they both just look like cats.. but also by RAW you can make a simple roll and tell that one is a cat and one is an extraplanar being.

I'm not planning on going to my DM with this (mine flies around too much for it to be an issue) but rather its just something that has been bugging me since I first read the description.

Am I just reading too much into it?

thoughts?

-S

[Turin the Mad]

I would ball park the Knowledge (planes) check at a DC 12. The description of the silvaneshee as a "cat" is rather vague. At 20 pounds it's about par for a very large male Bengal rather than a Maine-coon it is late and I cannot recall the proper spelling which are generally large and quite "fluffy" as compared to being sleek and muscular (which it sure would be at 20 pounds of house cat).

The violet eye coloration and specifically the unusual white blaze on the chest are the two big clues that the Knowledge (planes) check would clue in upon. If they are considered "rare", bump the DC up to a 17.

Circumstantial modifiers could also apply at the GM's discretion, primarily having to do with the background of the creature attempting the check.

[Morgen]

Your reading too much into it. You should describe the creatures how they look unless they are actually taking steps to disguise themselves.

There will be obvious things about some creatures that you shouldn't hammer on your players for guessing about.

[Ross Byers]

Keep in mind that just because it looks like a cat doesn't mean it acts like a cat. A silvanshee is considerably smarter and has more abilities than a housecat: it is quite possible some bit of un-catlike behavior is what would clue in a canny character what is going on.