We didn't know about grapes when we got our Tilley. So we gave them to her, thinking that they would be nice and cooling for her, as we got her in the middle of a heat wave, just like frozen peas.
She went utterly bunkers when she got them and played with them for 10-15min, throwing them about, jumping to and from them, kicking them, running about - having a whale of a time.
Then she just left them be, when they got warm.
We stopped giving them to her as that was just wasting food and then we read about it ...