Monkey-san.

Aah! It's a kind of monkey language only they can hear I came up with.

It's like dog whistles.

I could hear you perfectly though...

But I get it.

What did you just do?

Monkey-san.

I wanna join toooooo ♥

Shouldn't they go fix their heads at the dock?

Evidence.

The Heavy Cruiser Maya had a small monkey as their pet, which was kept on board by the aircrew. After surviving The Battle of the Philippine Sea together with Maya, the aircrew and their pet monkey were disembarked.