Many animals are colored so they can blend into their surroundings. This is called camouflage. The most common camouflage colors are brown and green.
A Gaboon viper snake, for example, has a pattern of brown and tan colors that help it blend in with dry leaves. Its camouflage allows it to hunt for food easier.
The lima shrimp also blends in with its environment. This small, bright red crustacean camouflages well because the other animals around it share the same bright coloring. Because of its camouflage, the shrimp can wait for its prey and captures it as it floats by.
Another creature that camouflages to hunt is the scorpionfish. The scorpionfish is almost impossible to tell apart from the sea floor, so its prey does not spot it.
Some spiders live in flowers and adapt to be the same color as the pedals. Like many other animals, the spiders disguise themselves to hunt the insects they want to eat and hide from the animals that want to eat them.
[Source: Amazing Animals: Colors]