The colorful and cunning octopus is a master of disguise. By flexing and relaxing muscles underneath its skin, this cephalopod activates color-changing sacs full of pigment, called chromatophores, to change its appearance very quickly. These sacs can change the strange-looking deep sea denizens from black to brown, orange, red, or yellow. One scientist documented an octopus changing the color of its skin 177 times within an hour.
An octopus changes its color to hide from predators. They also can change the texture of their skin, manipulating papillae to create everything from small bumps to tall spikes, to match the texture of rocks, corals, and other marine objects.
Eight arms and three hearts:
- Octopuses sometimes deliberately sever an arm in order to distract a predator long enough to get away. Like a starfish, the arm will grow back.
- Octopuses are able to close off a severed artery to reduce blood loss. Their blood is blue, not red, thanks to a copper content (instead of iron).
- Octopuses have three hearts. The main one stops beating when the animal is swimming, so it can't swim very far before tiring. They prefer to walk along the ocean floor.