The world has five oceans that make up approximately 71% of the Earth’s entire surface, measuring roughly 361 million square kilometers. At least half of this area is over 9,800 feet deep, and all of the oceans are composed entirely of saline water – salt water.
The Pacific Ocean is the largest. Located between North America, South American, Asia, Antarctica, and Australia, the Pacific covers 1/3 of the Earth’s surface, more space than all of the world’s continents combined. It is home of the Ring of Fire, the volcanic regions on the West, North, and East rims. The majority of the world’s marine animals can be found in the Pacific Ocean in some area or another.
The Atlantic Ocean is the second largest. It lies between North and South America, Europe, and Africa. The “youngest” of the oceans, it probably didn’t exist until 100 million years ago. With a deepest depth of 8,381 meters, it spans 106.4 million square kilometers, one fifth of the Earth’s surface.
The Indian Ocean is the third largest. Surrounded by Southern Asia, the Arabian Peninsula, Australia, and Antarctica, its deepest point is 7,450 meters. It covers 20% of the world’s surface, meaning it spans 73,556,000 square kilometers.
The Arctic Ocean is the smallest of the Oceans and it’s surrounded by the Bering Strait between Alaska, Russia, Canada, Greenland, and Denmark. Its deepest point is measured at 4,665 meters and it is divided into two basins, the Eurasian Basin and North American Basin. The central part of this ocean is permanently covered in ice.
The Southern Ocean, also known as the Antarctic Ocean or the Great Southern Ocean, circles Antarctica. It is the fourth-smallest of the oceans and relatively new in terms of definition being officially named only in 2000. It spans 20,327,000 square kilometers and its greatest depth is 7,235 meters.
The world’s marine animals call these oceans their home. Some of the most familiar animals living in the ocean are whales. Like other types of mammals, whales give birth to live young and nurse them, unlike most fish. However, they have flippers and lack hind limbs. There are two types of whales: baleen whales and toothed whales. While a baleen whale has a sieve-like mouth that is used to filter plankton or other small animals from the water, a toothed whale preys on fish and squid. The Blue whale is the largest animal to ever have existed. A typical Blue whale is 108 feet long and weighs 190 tons. Interestingly, it does not eat fish but rather small crustacean animals known as krill.
Dolphins are also one of the more well-known species of marine animal. There are over 40 species of dolphins and they can range from the small Maui’s Dolphin, which is about 4 feet long and weighs 90 lbs, to the huge Orca, which is actually a dolphin, despite its name. Orcas can weigh over 6 tons and be up to 26 feet long. Dolphins are very common in the shallower waters near continental shelves.
Sharks are considered to be the king predator of the ocean. They are actually a type of fish that can range in size from 7 inches in length (lantern shark) to 39 feet (whale shark). Sharks have a special skin covering that protects their skin from damage and they have several sets of teeth so that if one is knocked out, another takes its place. The great white shark is the best known. Feeding on almost any type of meat, it can be over 20 feet long, weighing up to 4,938 pounds.
Squid also call the ocean home, and there are over 300 different species. They have a unique shape and have eight “arms” as well as two tentacles that are arranged in pairs. The outer skin used to be a hard shell but it’s now much softer. Squids can change their coloring to match their surroundings and they have three hearts.
Meanwhile, octopi are very common amongst the world’s coral reefs. They have no skeleton at all; the hardest part on their body is the beak. Considered highly intelligent, they have two eyes and four pairs of arms. There are over 300 species of octopi and all of them are venomous. When startled, they release ink to try and distract predators. Like squids, they have three hearts as well.
Turtles live in shells that are actually made of cartilage developed from their ribs. There are over 300 species of turtles identified today. Turtles are cold-blooded, breathe air, and do not lay their eggs underwater, making them a bit unique when it comes to the ocean’s animals. The largest turtle can grow up to 6 feet long and weigh over 2,000 pounds, while the smallest measures 3 inches and 4.9 oz.
And then, there’s the fish, which are abundant in every ocean. A fish is any type of vertebrate that lives in the ocean. Cold-blooded, it has scales and fins. Fish breathe through gills that are able to extract oxygen from the water around it. The smallest fish is only ¼ of an inch long while the biggest fish is over 51 feet long. Their diet ranges from plankton to small crustaceans to even other fish. With over 28,000 species of fish known to man, their diet varies greatly.
The world’s oceans are truly incredible. For people who really want to see all the colors and wonders of the oceans, they should get some travel insurance, and take a dive into a most amazing world.