I just half-saw a TV documentary on hippos and there was a bit in it where a hippo research guy was recording the sounds hippos make underwater. It was quite interesting because their underwater noises are all whines and clicks and other dolphiny-type things, completely different to their above-water noises. Anyway, he was doing this at Toledo's hippoqaurium, and I was just wondering if the zoo has an underwater microphone permanently in the hippo tank because I should imagine that would be fascinating for the visitors.