Sylestia.com (DeathlyFrostbite, my ID is 12176 in case you are interested)
AnimalJam.com (swirlingstar)
I also play these sites *sometimes*:
ClubPenguin (Rayneb0w, I think. xD)
I used to play Pony Island but it got boring :/
There are three dangerous things on this world: Rainbow potatoes, polka-dotted llamas, and completely random people like me. (so watch out) DeviantART: deathly-frostbite.deviantart.com
I used to be on a bunch of sites, but I keep getting chased off by jerks...
On Valenth/Squiby, one of the two site owners stalked my every post and bullied me until I left the forums, then froze five of my friends and fired my mod friend for something they didn't do because she didn't like that I used deviantart to upload three of the pet banners I made for my friends. So I quit for good.
On Chickensmoothie, I had played for about three years when the forum base became really super catty and defensive. I quit because the drama was so insane it was affecting my personality IRL, and have no intention of returning.
On Marapets, the forum base is arguably worse than Chickensmoothie. I still play, but I avoid the forums like the plague.
I've had similar problems elsewhere, but they weren't pet sites.
Has anyone heard of Exhibited? It's a site where you breed raptors, and other dinosaurs. I joined as qweee, but have yet to receive my activation e-mail. Anyone else play it?