I'm going to come out and say it: this guy is an idiot. He plausibly has some narrow domain expertise in paleontology, but outside of that, he has no clue what he's talking about. Even on Earth, the most intelligent species are dolphins, crows and chimpanzees (including us); any alien intelligence is going to be more different from you than you are from a dolphin or bird. Star Trek aliens ("rubber forehead aliens") are more similar to us than we are to chimps; to call that "unrealistic" is a huge understatement. And, searching for water? Really? Water is composed of two elements: hydrogen and oxygen. Hydrogen is the most abundant element in the Universe, and oxygen is the third most abundant (after hydrogen and helium). A shortage of water is about the last problem an intergalactic civilization is going to have.