Manta Rays

Manta rays are the largest member of the ray family, growing up to 25 feet across. While most fish swim, rays fly gracefully through the water by flapping the edges of their fins like wings. Rays are actually relatives of sharks.

Manta rays are a favorite among divers because they are so large and beautiful, but also very gentle. They are said to often become curious about divers and interact with them. They have the largest brain-to-body ratio of any of the shark family. They are also sometimes found in groups or even large schools.

Manta rays are sometimes referred to as devil rays because of the hornlike projections around their mouths. These are actually used to funnel food into their gaping mouths. They feed exclusively on plankton, which they scoop into their mouths as they glide along the currents. Manta rays swim slowly, often doing loops and dives as they seek out plankton.

With their huge wingspan, one often wonders if they could fly. In some ways, they do. Rays have been observed leaping completely out of the water for short periods of time. Naturally gravity takes its toll but they get some considerable air time before plunging back under the waves.

If you want to see a giant manta ray in person, you can find one swimming along with 3 whale sharks in the Georgia Aquarium. I got to watch this graceful giant up close on my recent visit there.

Jellyfish

Jellyfish are cnidarians, related to sea anemones and sea slugs. They consist of a dome-shaped body and tentacles that trail behind them. Jellyfish are able to swim through the water by pulsing their jelly-like bodies. Their tentacles are covered in poisonous stinging cells called nematocysts. These tentacles can paralyze or kill fish. Some jellyfish, like the box jellyfish below, are powerful enough to kill humans. The venom in a box jellyfish can stop a person's heart in less than 3 minutes.

While most jellyfish are relatively small, some can grow to enormous sizes.

During certain times of year, jellyfish can be found in huge numbers, clouding the seas with their pulsating forms.

Some jellyfish can even glow in the dark.

Great White Sharks

Great White sharks are among the fiercest and most deadly predators in the world. They are among the few species of sharks that have a reputation as man-eaters. They are some of the most efficient and powerful predators in the world. Here is some breathtaking video footage of great white shark attacks from the series "Planet Earth".

[WARNING: Not safe for small children or people who love seals]

World's Deepest Fish

Scientists have discovered fish living nearly 5 miles below the surface of the ocean. There is no light at this depth, and the pressure is enough to easily crush nearly any living thing. The pressure is about as much as the weight of 1,600 elephants. The water temperature is nearly freezing. It seems impossible that anything could survive in these conditions, yet there is life here.

This species of snailfish is able to thrive in large numbers in this extreme environment. Scientists had to specially design the camera equipment so it wouldn't be destroyed by the crushing pressure. It was previously inconceivable that anything could live at such depths, but it seems that no matter where we search on earth, there is always life.

Whale Shark

Whale Sharks are the biggest fish in the world. Blue whales are far bigger, but they are air breathing marine mammals. Whale sharks can grow up to 40 feet long and weigh up to 15 tons. Strangely enough, they are one of only 3 species of sharks in the ocean that are not harmful to humans. In fact they are often photographed swimming peacefully with divers.

These gentle giants do not have the rows of razor sharp teeth fitted in most of their relatives. Instead of prowling constantly in search of blood, they casually glide through the ocean with their huge mouths open wide. They are filter feeders. This means they strain out microscopic plankton from the ocean around them as their food. They are another example of one of the biggest animals in the ocean feeding on some of the smallest.

Giant Squid

Sailors used to tell stories of the Kraken, a great sea monster with long tentacles which could swallow ships whole. It is believed this mythical beast was inspired by the real monsters in the ocean, the giant squid. This creature has been a mystery to science until very recently. The largest giant squid on record is over 60 feet long. It is by far the largest invertebrate in the world, and the biggest mollusk in the ocean.

Giant squid are very elusive and live in such deep water it is almost impossible to seek them out. Scientists knew these squid must be real because they found giant suction cup scars on Sperm-Whales that were known to feed on these giant mollusks. Giant tentacles were then found in the belly of dead Sperm-Whales, and then some bodies of giant squid were found washed up on the beach. But for centuries no living specimens were found, until 2004.

The photo above was taken by a Japanese research team that captured the first live giant squid on record. It was said to have put up quite a fight, but the team finally caught it and pulled it on board. It died while being captured, but its body was measured at 24 feet long. This was not a fully grown specimen. Giant squid are commonly known to grow over twice that size.