Situation
A level 8 Celestial Warlock, Pact of the Tome, has an owl familiar1. The party Wizard casts polymorph on the Warlock such that a Tyrannosaurus Rex (INT 2, Wis 12) is now standing there.
How it was ruled
While your familiar is within 100 feet of you, you can communicate with it telepathically. (PHB, find familiar, spell description)
We (DM and I) guessed that the telepathic connection between the Warlock and the familiar remained, but we weren't sure.
The target’s game statistics, including mental ability scores, are replaced by the statistics of the chosen beast. It retains its alignment and personality. {my emphasis} (PHB, polymorph, spell description)
The "retain its alignment and personality" was our basis for thinking that the owl would stick around and still have contact with the Warlock/T Rex. We weren't sure what the familiar could do, now that the Warlock's intelligence was 2. (Normal INT of that Warlock PC is 12). We did allow that a 12 Wis was helpful, but since INT is the "memory" trait we felt that the Warlock might have taken a hit on mental interactions (such as 'who is that talking in my head?').
Question(s)
The directly related questions to answer are:
- Does the familiar stick around to assist the polymorphed PC? (If No, then the rest is moot)
- What actions can the familiar take if its caster is polymorphed into a beast?
We weren't sure. The DM (for simplicity's sake, six players to take care of) let the owl fly around and do its usual scouting such that the T Rex could learn from the telepathic communication, but the T Rex was not able to share that info with the rest of the party2. The owl did a couple of flyby/Helps in combat to give the T-Rex advantage on a bite attack, but we (the DM and I) weren't sure, after the battle, if we'd gotten that right. (This familiar does that in some, but not all, of our combats depending on the situation).
When we took a look at the rules it wasn't clear. When I searched Familar + Polymorph at RPGSE I came up empty, beyond the two rules cited above and this:
Your familiar acts independently of you, but it always obeys your commands. In combat, it rolls its own initiative and acts on its own turn. A familiar can't attack, but it can take other actions as normal.
We think that an INT 2 (Wisdom 12) T Rex (with a Warlock's personality) could, if the telepathic communication is still active, issue commands to the familar to "do this, I need it" but that's about it. I wanted to not get more out of a 2 INT than seemed reasonable to the rest of the table.
Question restated
If the familiar's caster is polymorphed, will the familiar remain and function normally? If yes,
What can the familiar do while the caster is polymorphed into a beast?
If there are rules, rulings, or Save Advice that covers this that we missed, that would be helpful. If there's a glaring gap in how it was ruled, that would also be useful. (We expect for there to be T-Rex shenanigans, and Giant Ape shenanigans, in the near future in the city where we deal with a grand vizier who has been spying on us).
1 Book of Shadows, level 1 spell, find familiar
2 The Totem Warrior Barbarian didn't choose to cast the speak with animals ritual that they could have, even though I, OOC, suggested it
Related questions include: communicating with a familiar , minimum INT for using abilities, and what can my familiar do?