Loukanikos and the Greek protests

I've read that Loukanikos ('sausage'), the political dog, is out on the streets again with the Greek people protesting about their politicians' mismanagement of the economy.

The Australian recently led an article with a mention of Loukanikos.

A veteran protester, Loukanikos, dared to show his face among rioters wearing balaclavas in December 2008. He dodged tear gas last year and he faced down riot police last week.

But Loukanikos is an unlikely mascot for the violent uprising. For "Sausage" - as his name translates - is a furry stray dog. This underdog has come to symbolise a struggle threatening to bring down the euro.

However...

I looked at old footage of Loukanikos on the streets, and the last still photo is interesting. How come he has tags on his collar if he's a stray?