Sunday morning, I had to get up at 5:30 AM (don't ask). As my husband didn't, he wisely chose to sleep in another room, meaning that I was all alone, but with a cat. The window was wide open, and the other cat was outside.
I didn't set an alarm, as it's on his side of the bed, and set to a time he normally needs. I didn't want to change it, and as I get up early anyway (the internal alarm), I was a little concerned, but just figured I'd wake up.
At 5:30 AM exactly, both the indoor cat and the outdoor cat, who was sitting directly under my window, commenced caterwauling. (I just then realized where the term originated.) "Poor, poor pitiful me -- feed me", they cried, loudly and in stereo, despite having been fed less than 8 hours before.
I was amazed and grateful -- they'd awakened me right on time! Do you suppose they telepathically knew what I needed? Just asking...