When do pets go from Uncommon to Rare?

[purrme31]

I've always wondered how pets go from uncommon to rare or start out as rare? And how often do they move up to rare? Anyone's help would be appreciated! Thank you!

[Shian]

Pets go up in rarity as time goes by. It's different for each pet.
The "08 rare line" is down to March of 09 as Feb 09 pets just became rare, so March will follow soon.
Event pets like candy hunt pets go rare in just a few months, but they often start out as uncommmon.

[purrme31]

Thanks Firestar!