Specifically tried (so far) the " Gorestained Piglet", aka Cursed Piggy, that is only found in Waycrest Manor. Beast Lore says “Tameable” but when you try taming, it errors saying “Not Tamable”. So which is it Blizzard.
Look on petopia and for some reason the snakes in dungeons like the snakes in the pit in front of the first boss of Gundrak on Heroic it will show cannot be tamed but if you go outside and switch it to Normal difficulty then you can tame them…