Octopuses have eight arms that trail behind as they swim and have no internal or external skeleton. Dolphins are marine mammals closely related to whales that live in shallow seas and eat fish and squid. Sea turtles spend most of their time submerged but surface to quickly breathe air through a rapid exchange in their lungs adapted for diving. Sea stars are echinoderms with the scientific name Asteroidea and are sometimes called starfish, which can also refer to closely related brittle stars. Penguins are flightless birds that live in the southern hemisphere and Antarctica, having black and white plumage and wings that become flippers.

1. Lucia Francisco Mera Animals of the sea

2. octopus 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.

3. dolphin 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.

4. sea turtle 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.

5. SEA STAR 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.

6. penguin 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.