As in, summoned snakes aren't immune to mind spells, but summoned cats are. Not sure if it's a bug or intentional to make l2 summons better than L1.
Snakes are immune to mind spells and animals like cats are not.
Summoned ones aren't. I know because Ghouls can sleep them but not cats.
Unless this has been fixed, that means the summonable ones don't match up properly.
Addendum: Summons will not necessarily match their 'wild' counterpart.
You changed your post!