"Oldie is a Sweetie" - Queensland Times Newspaper in Ipswich Australia.

Wow, I wonder how they can prove that he's that old. I don't know what "carbon dating" is but it's great that he's had a long life.

Carbon dating is used for very ancient materials. Carbon decays at a steady rate, and they know how long it takes for it to lose half of its mass. They can use that to figure out an approximate age.

Applied to a guinea pig, it's a joke, as the half-life of carbon is over 5700 years.