The octopus makes its home in oceans around the world, from shallow reefs to the deep sea. This mollusk is from a few centimeters to several meters across, depending on the kind. Few animals could survive there, but the octopus's body and habits are a good match for it.
One reason the octopus survives is eight arms covered in suckers, which grip rocks and pry open shells. It also has a cloud of dark ink it can squirt, which hides it while it escapes from predators.
The octopus is a carnivore, which means it is an animal that eats other animals. Its food includes crabs, shrimp and clams. To find food, it squeezes its soft, boneless body through tiny cracks to hide.
Young octopus are called hatchlings. A mother octopus guards her eggs for weeks and does not leave them, even to eat. An octopus has three hearts and blue blood.