The octopus is an invertebrate lacking a backbone which enables it to crawl through tiny cracks and crevices. It also allows them to hide in very small places where they like to spend the majority of their time to escape detection.
The eight arms, or tentacles, of the octopus are like separate creatures. Each is loaded with nerve cells, enjoys a great deal of autonomy, and can regrow when needed. One researcher cut the nerves connecting an arm to the central brain and then stimulated the skin on the arm. The arm behaved normally and even reached out to grab food when given the opportunity.
Each arm is lined with powerful suckers that can grab prey and pass it from sucker to sucker, as if along a conveyer belt, until it comes into contact with the mouth which is located in the center of the arms.
In the wild, most female octopuses will lay hundreds to thousands of eggs only one time in her relatively short life. She will guard them constantly until they hatch. She will not even leave them to hunt for food, and thus starves herself for the rest of her life. She usually dies shortly after her eggs hatch.
When the eggs hatch, the newly born are extremely tiny. They are exact replicas of an adult, and they grow very quickly. They become part of the ocean's plankton population which feeds numerous other species of life. If they survive, they eventually become large enough to settle on the bottom and continue their life. Since only a few survive to become adults, each female octopus must lay excessive numbers of eggs in order for the species to survive.
Octopuses are highly individualistic in their behavior. They can be shy, aggressive, friendly, curious, standoffish, or playful. When upset, they may squirt a stream of water out of their siphon at whatever is displeasing them.
Octopuses can rapidly change color, pattern, and texture of their skin for purposes of camouflage or to display their mood. They also can discharge a dark fluid from their ink sac that contains the dark pigment melanin found in many other animals including humans. The ink also contains other chemicals that irritate the eyes, clogs gills, and blocks the action of several common hormones. It is thought that this ink may be used to hide, confuse predators or subdue prey.
Larrie Stone is a retired Dana College science professor.
