Thats what i thought originally but getting confised when i read this page: http://googlewebmastercentral.blogspot.com.au/2011/12/new-markup-for-multilingual-content.html
Specifically this bit:
Annotating pages as substantially similar content
Optionally, for pages that have substantially the same content in the same language and are targeted at multiple countries, you may use the rel="canonical" link element to specify your preferred version. We’ll use that signal to focus on that version in search, while showing the local URLs to users where appropriate. For example, you could use this if you have the same product page in German, but want to target it separately to users searching on the Google properties for Germany, Austria, and Switzerland.
And read in conjunction with this article:
http://searchengineland.com/cutting-through-the-confusion-of-googles-guidance-to-multilingual-website-owners-113586
Specifically this bit:
The Effect Of Combining Canonical Tags & Hreflang Tags
Not forgetting that the canonical tags should only be used with content in the same language, when would we use both?
Well firstly, the use of both would involve what I usually call world languages such as English, Spanish, French or Portuguese. These languages are used in many countries and, whilst there are variations between the use of these languages in those countries, the variations are sometimes small.
Additionally, multinational publishers often save costs by using one version of the language for all countries speaking that general language, thus ignoring the regional variations. In other words, for Spain and Mexico, Google is presented with exactly the same content, letter for letter.
The canonical acknowledges that this is the same content. The Hreflang tag identifies which URL should be displayed in different sets of results.
So, in other words, canonical + Hreflang = same content + different URL.
Google knows the content is the same, but displays the correct URL for the Google domain search (e.g. google.com.mx will see the relevant URLs for Mexico displayed in the results).