How do pets age?

[rabbitlover12]

I have a couple of deer that I purchased with tokens three site cycles ago, but the age is only 2 days old. I don't understand how they calculate how many days a pet has been alive, I thought it happened at server rollover but I'm not so sure any more...

[Senbonzakura]

pets age based on the exact time you adopted them at your current time, not server time^^

So if I adopted a deer on August 4th at 10:13am, it will turn 1 day old on August 5th at 10:13am^^

[Keir;]

and if you'd like to view the exact time a pet was adopted, you can just hover over the adoption date that it showed below them in your pet group or pet page! that'll show you the exact hour, minute, and second that they were adopted, and therefore the exact time they will age up ^^