A Quiz About Marine Life

Octopuses have three hearts; a systemic heart that circulates blood round the body and two branchial hearts that pump it through each of the two gills

Male seahorses give birth by releasing their young offspring into the water once the eggs hatch

The amount of teeth a shark can lose over its lifetime does depend upon the species. The sharks that have several hundred teeth in their jaws will lose more teeth overall than the sharks that only have a dozen teeth. So, amazingly, a shark can go through about 30,000 to 50,000 teeth over the span of its life

Sharks have skeletons made of cartilage and connective tissue. Cartilage is flexible and durable, yet is about half the normal density of bone.

Yet despite these inhospitable conditions, the Arctic Ocean is teeming with life. Great polar bears roam the Arctic ice and swim the Arctic seas. Supporting these top predators is a complex ecosystem that includes plankton, fish, birds, seals, walruses, and even whales.

Despite their tremendous size and intimidating appearance, whale sharks are commonly docile and approachable. Whale sharks are filter feeders and sieve plankton through their gills for much of their nourishment. They also sieve squid, krill, and small fish.

All penguins live in the Southern Hemisphere, though it is a common myth that they all live in Antarctica. In fact, penguins can be found on every continent in the Southern Hemisphere.

n the process of laying eggs scientists have observed tears coming out of turtle's eyes. However, that doesn't mean sea turtles are crying. The tear is a result of a process through which turtles get rid of the excess of sea salt.

Dolphins are mammals and breathe air into their lungs, just like we do. Dolphins cannot breathe under water like fish can as they do not have gills.

Marine animals are divided into three groups: zooplankton, nekton, and benthos. Zooplankton are drifting animals. Nekton are the free swimmers and probably the largest portion of familiar animals found in the ocean belong to this class. The third type of sea animal spends its entire life on or in the ocean bottom. This group of marine animals is called the benthos.

Both male and female walruses have long ivory tusks, although the tusks of the males tend to be longer and thicker than those of females. The tusks are the walrus' very long upper canine teeth, and they grow to an average length of about 36 cm / 14 inches, but they can grow as long as 100 cm / 39 inches in males.

Like other large whales, blue whales are threatened by environmental change including habitat loss and toxics. Blue whales can also be harmed by ship strikes and by becoming entangled in fishing gear. Worldwide, the green turtle continues to be hunted and its eggs harvested. Much of that is for human consumption, but trade of turtle parts remains a profitable business. Uncontrolled coastal development, vehicle traffic on beaches, and other human activities have directly destroyed or disturbed sea turtle nesting beaches. Dugongs are threatened by sea grass habitat loss or degradation because of coastal development or industrial activities that cause water pollution.

Most species of shark eat things like fish, crustaceans, mollusks, plankton, krill, marine mammals and other sharks. Sharks also have a very acute sense of smell that allows them to detect blood in the water from miles away.