在地球的海洋深处隐藏着一些奇怪的生物。其中包括寿命长达400年的格陵兰鲨，以及地球上最大的无脊椎动物——巨型乌贼。

The ocean covers over 70% of the surface of our planet, though, according to the National Ocean Service, 95% of it remains unexplored. This is because under the surface is a dark and hostile environment with unrelenting high pressure, freezing temperatures and bizarre creatures in the depths.

The Census of Marine Life reports more than 17,000 species living in the deep sea. The Greenland shark can live in depths of 7,200 feet and is a rarely seen Arctic predator said to live to 400 years old and reach 23 feet in length. In order to battle the icy depths, Greenland sharks have chemicals in their skin which prevent ice crystals from forming on their body.

Another deep-sea creature is the giant squid, an animal that remains a mystery to scientists despite being the largest invertebrate on Earth. Living far below the surface, what we know has largely come from carcasses being washed ashore. Marine biologists have found that they feed on fish, squid and possibly even small whales. They find prey using eyes which are ten inches wide, roughly the size of a dinner plate!

Other unusual creatures include the vampire squid, which lives 2000 to 3000 feet under the ocean and is so-called because of its dark cloak that connects its eight arms. There is also the dumbo octopus, named due to its resemblance to the elephant from the 1943 Disney film Dumbo, with its protruding ears. Another unique creature is the anglerfish known for the light that hangs from its head.

So, enjoy swimming, but don't venture too far down – you never know what is lurking beneath!