Dolphins can imitate a variety of sounds from their environment almost indistinguishably from the original. They are talented mimics that can even copy human speech. Sharks have a cartilaginous skeleton unlike bony fish and are divided into 8 major groups based on body shape, head features, gill openings and other distinguishing characteristics. There are over 350 shark species. Grampus whales, also called sperm whales, have males that can reach 9.5 meters long and weigh up to 8 tons while females are smaller, reaching up to 7 meters and 4 tons. They have a distinctive black body with white belly and spot. Plankton consists of a wide variety of small plant and animal organisms that drift with