Creatures of the Deep Sea

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Deep-sea creatures are the animals that live in the deepest, darkest parts of the ocean — below about 200 metres, where sunlight cannot reach. This freezing, pitch-black world is one of the hardest places on Earth to survive: there is no light to see by, the water is bitterly cold, and the weight of the ocean above presses down with crushing pressure.

To cope, deep-sea animals have evolved remarkable adaptations. Many make their own light inside their bodies, a trick called bioluminescence — the anglerfish, for example, dangles a glowing lure to attract prey. Instead of hard, air-filled bodies that would be crushed, creatures like the vampire squid have soft, jelly-like, watery bodies with no air pockets, so the pressure has nothing to squash.

Learning about the deep sea introduces the ocean's five zones, each darker and colder than the one above, and shows how living things adapt to extreme conditions. It also explains why scientists have explored less of the deep ocean than the surface of the Moon.

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Frequently asked questions

What is a deep-sea creature?
A deep-sea creature is an animal that lives in the ocean below about 200 metres, where almost no sunlight reaches. They survive in cold, dark water under enormous pressure.
How do deep-sea animals make light?
Many deep-sea animals produce their own light inside their bodies through a chemical reaction called bioluminescence. They use this glow to attract prey, find mates, or scare away predators.
Why doesn't the deep-sea pressure crush these animals?
Deep-sea animals have soft, watery, jelly-like bodies with no air pockets inside them. Because there is no trapped air to squash, the heavy pressure of the water has nothing to crush.
What are the zones of the ocean?
The ocean is divided into layers, or zones, stacked like a tall cake. Going downward through the sunlit, twilight, midnight and deeper zones, each layer becomes darker, colder and more crushing than the one above.
What is the anglerfish famous for?
The anglerfish is famous for the glowing lure that dangles in front of its mouth. The light attracts smaller animals in the dark, and when they swim close, the anglerfish snaps them up.

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