An estimate of over 2-million aquatic species dwell in our oceans. And while it is easier to see seals, walruses, and sea lions hauled on rocks or beaches to sun themselves, most others aquatic dwellers will take a little more effort. Fortunately, many areas offer whale-watching excursions so we can go into their living room to winess their splendor. There are over 120 species of marine mammals...Walter Pietrowicz
Representing the order, Cetacca, there are over 80 species of marine mammals that include all whales, dolphins, and porpoises. The word "cetacean" is from the Latin "cetus", which means large sea creature, hence exemplifies by the Blue Whale as the world's largest animal.
• SEALS-SEA LIONS & MORE
Family: Otaridae includes over a dozen of fur seals and sea lions. What's the difference? Mainly sea lions are a lot more noisy (can't here the difference here) and a small outer ear to hear their vocals. Seals lack an external ear.