Survival of the fittest on the ocean's reefs

The variety of life found on coral reefs attracts some of the ocean’s deadliest predators. In response, creatures that live by the reef have evolved a fantastic range of survival strategies to avoid being eaten.

Some animals work together to ward off or evade predators, while others use camouflage, colourful warnings or toxic defences. A flash of colour or a swish of the tail can be the difference between life and death.

Nudibranch

These slugs of the sea are soft-bodied. To protect themselves they resort to chemical warfare.

Nudibranchs eat sponges and recycle the poisonous chemicals the sponges contain, using them within their bodies to deter animals from eating them. Their bright colours warn would-be predators to stay away.

Cuttlefish

Their name is misleading as the cuttlefish are not fish. They are actually molluscs, like squid and octopuses. Cuttlefish can change their skin colour and texture to provide camouflage or to communicate with each other.

When hunting, a cuttlefish sends shimmering waves of colour along its body to distract or confuse its prey.

Hermit crab

The hermit crab has a soft abdomen which it protects by making its home in shells left empty by dead sea snails and other animals. As the hermit crab grows, it has to find a larger shell.

The right shell is hard to find and hermit crabs even queue up in size order next to empty shells - each crab is waiting to move into the vacated shell of the larger crab in front of it.

Hairy frogfish (Antennarius striatus)

Camouflage is the hairy frogfish's main defence against predators. Within weeks it can adapt the patterns and colours on its body to match its new surroundings.

This also helps the frogfish to find food. Camouflaged against rocks on the seabed, it uses a twitching lure protruding from its head as bait to attract unsuspecting prey.

Banded sea krait (Laticauda colubrina)

This sea snake can fool predators into thinking that the tip of its tail is its head.

While it is searching crevices for food, the sea krait uses its tail to mimic the movement of its head. Similar markings on its tail and its head add to this illusion.

This trick reduces the chance of being attacked by predators, who think the sea krait is looking right at them.

Clownfish

Clownfish have a mutually beneficial relationship with sea anemones, which they protect aggressively, even from humans.

The clownfish has a protective coating of mucus, allowing it to take refuge in the stinging tentacles of the anemone without being stung. In exchange, the clownfish protects the anemone by chasing away predatory butterflyfish.