* First Year: A guinea pig ages quickly in their first year, equivalent to about 18-20 human years.
* After First Year: Each subsequent guinea pig year is roughly equivalent to 6-7 human years.
Example:
* A 2-year-old guinea pig is approximately 34-36 human years old.
* A 5-year-old guinea pig is roughly 60-65 human years old.
It's important to remember these are estimates, and each guinea pig ages at their own rate.