Digestive System of an Octopus

Mouth and Beak

• An octopus has a radula, a tongue-like organ covered with raspy teeth. However, most of the tearing and cutting is done by a horny beak in the buccal cavity, the octopus version of a mouth. The lips of the mouth are ridged to help maintain a grip on the victim. Once the prey has sustained tissue damage, one pair of salivary glands secretes digestive enzymes while another pair secretes a toxin which immobilizes the victim. If the intended victim happens to be a clam, the beak and radula are used to drill through the shell and the digestive juices are injected to dissolve the connective tissues.

Esophagus and Crop

• The stunned and partially digested prey passes into the octopus' esophagus which is also equipped with more digestive glands. This organ then widens to form the crop which contains yet more digestive glands that perform the function of a pancreas and liver in higher animals. The crop forms a pocket for temporary storage of partially digested food before it passes to the stomach.

Stomach and Caecum

• An octopus' stomach is a very muscular organ. When the remains of the poor victim reach this stage, more pancreatic and hepatic enzymes are added via ducts from the caecum, an auxilliary tank for digestive components. After the food has been churned into a slushy mass in the stomach, it enters the caecum for the final stages of this part of the process. Before leaving the caecum, the food is filtered. Nutritive parts are retained for the body's use. Indigestible bits move to the next stage.

Intestine and Anus

• What remains from the victim, pieces of shell and bone, pass through the intestine before reaching the anus. The anus then exits the octopus through a fold in the mantle, the outer covering of the body, via a siphon near the head. Octopus eggs and ink are excreted through the same opening.

Conclusion

• Given the rather violent nature of its digestive tract, an octopus would make a terrible pet. The various species are considered to be the most intelligent invertebrates in the world, roughly as smart as the average house cat. They have been known to remove the covers of the tanks in which they are kept in captivity.