A Cetacean is an animal that belongs to the Order: Cetacea This includes Whales, Dolphins and Porpoises. Cetaceans are mammals fully adapted to Aquatic life and there are about 90 species.
Well, a typical "he" will be male. In human, this means that "he" will produce hormone testosterone and not estrogen which is what "she" will produce. Also, "he" will not have a mammary glands...