Where do frogs go at night?

Yesterday night, I could hear a frog doing this annoying croaking thing -___- (It does it like every 7 secs. Lol) So I went outside and there was 2 frogs ! :o and I was really surprised because I've been hearing that noise and I've never seen them during the day.. Where are they at during the day? I have a pond and it surrounded by rocks big and small.. Idk I that helps..