Reproduction
The class Cephalopoda reproduces sexually. Adults are dieocous and have internal fertilization. They have a direct development where the juvenile hatches directly from an egg and will look like a smaller version of the adult.
Squid have a very interesting way of breeding. First around dawn, they can be seen swimming in large circles to attract a mate. Eventually they will pair up with the opposite sex and that will be their mate.
Males have one modified short arm called a hectocotylus that they use to store spermatophores and transfer them directly into the female during mating. The sperm from the males are placed inside the ink sac on the underside of the female to fertilize her eggs. Thousands of eggs can be inside of a female at one time. She will then distribute the eggs in a safe hidden place and leave them there for about 8 weeks. The females leave their eggs and usually die shortly after laying them because of their short life cycle.
Once the babies hatch, they already know how to swim and start fending for themselves. Most of these babies die within the first couple days of hatching but the lifespan of a juvenile that beats these odds will only live for about two years.