Lucia Francisco Mera

A octopus has eight arms, which trail behind it as it swims. Most octopuses have no internal or external skeleton, allowing them to squeeze through tight places.

Dolphins are marine mammals that are closely related to whales and propoises. They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating fish and squid.

Sea turtles are almost always submerged but breathe air. With a single explosive exhalation and rapid inhalation, sea turtles can quickly refill their lungs when they surface. Their lungs have adapted to permit rapid exchange of oxygen and to avoid trapping gasses during deep dives.

Sea stars are echinoderms belonging to the class Asteroidea. The names "sea star" and "starfish" are sometimes differentiated, with "starfish" used in a broader sense to include the closely related brittle stars, which make up the class Ophiuroidea, as well as excluding sea stars which do not have five arms.

Penguins are a group of aquatic, flightless birds living almost exclusively in the southern hemisphere, especially in Antarctica, where they are most well known for living. Penguins have a black and white plumage, and their wings become flippers.