I saw these on the BBC website where they've been posted as 'Musical Rats'. I almost felt the need to point out that actually it's just the one rat
On the BBC pictures
, the fifth picture is the panpipes one, you can see a little tongue running along the top of the pipes (awwww...sorry, but rat tongues are cute [especially when they lick you to death]). So I am guessing they've used something like Nurish-Um, FerretVite, Nutrical, stuff rats can't resist really, to get the mouth in the right place for the photos.
I posted the BBC link to my husband, who just said 'all that proves is rats will put anything in their mouths'...