Possible Duplicate:
Why doesn't “its” have an apostrophe?

Generally, there is an apostrophe when someone possesses something:

That's Gerald's cat.

Gerald's cat is dead.

But when it comes to the possessive of it, its is correct, and not it's.

The common house cat is endeared for its ability to land on its feet.

Why is this? If Gerald's is correct, why is it's not correct?

  • maybe this is enough: the-editor.uphero.com/2011/02/24/its-or-its – Unreason Oct 26 '11 at 16:07
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    @Unreason: I see they give the example The dog's bark is worse than its bite on that link. To which I would add so it's its bark you should fear. – FumbleFingers Oct 26 '11 at 16:18
  • I swear I searched for a duplicate before this, and somehow didn't find it... Sorry. – user11550 Oct 26 '11 at 23:39

Think of "its" as going with "his" or "hers" - you don't use an apostrophe in those even though they are possessive.

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    And, to give the other half of the answer, "it's" is completely unrelated and is the contraction for "it is". – David Schwartz Oct 26 '11 at 16:15
  • @David alternatively it's from the middle English 'es' possesive and marks the missing 'e' – mgb Oct 26 '11 at 16:38
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    Actually, it's is the original form of the possessive. The apostrophe got dropped only recently. (Like, last century recently.) – RegDwigнt Oct 26 '11 at 16:53

There are two primary reasons

  1. Possesive pronouns do not end with 's (mine, yours, hers/his, ours, theirs)
  2. Ambiguity. "It's" is a contraction of "it is". In most cases, substituting "it is" for "its" in a sentence would result in nonsense, but I'm sure there are cases where it could still make sense, therefore changing the meaning. Either way it would be incorrect.
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