When the octopus breathes in, water flows over the gills and fills the mantle. When it breathes out the water is forced out a tube call the siphon. If an octopus is trying to escape a predator it can force water through the siphon rapidly and jet itself backwards. Octopuses have been known to travel many kilometres using jet propulsion. An octopus can also temporarily blind an attacker by squirting ink at it.
Most octopuses live only one or two years.
A female octopus will lay thousands of eggs and protect them until she dies. The Giant Pacific Octopus lays about 50,000 eggs and tends them for about 6 months. During this time she does not eat but spends all her time protecting the eggs from other animals such as sea stars and crabs. She will only produce one nest in her life. When the babies hatch they are not giants like their mother but about the size of a grain of rice.