Bloodvarks are useful working animals that are fun to have around, and they are ever so much help with shipboard security. Tree rats come in handy for the mischievious GM to let loose as an NPC's pet that gets free.
Generally, the Crested Jabberwok, although a magnificent animal, does NOT make a good pet (could someone please hand me my prosthetic arm, I can't find it without my glass eye).