At first glance, an octopus’s sucker looks like the simple suction cup that tips a toy dart or affixes a GPS to the windshield. In fact, it is a remarkably sophisticated organ that not only can attach to objects with varying degrees of force but also can maneuver them, thanks to specialized muscle groups.

The sucker has two chambers: the outer infun­dibu­lum and inner acetabulum. When it attaches to an object—a tasty clam, for instance—the muscles of the infundibulum reshape the sucker rim to conform to the shell surface, forming a seal. The muscles of the acetabulum then contract, producing intense negative pressure inside the water-filled interior of the sucker relative to the external seawater. This pressure differential generates suction. The more the muscles of the acetabulum contract, the higher the negative pressure and the firmer the sucker’s grip. So-called extrinsic muscles, meanwhile, permit the sucker rim to rotate the object in a full circle at a shallow or steep angle to the arm without breaking the seal or reducing the pressure differential.

This article was originally published with the title Sensational Sucker.

8 Comments

1. 1. madhawes 03:11 PM 10/6/10

   Can we look at the octopus as having a very large brain? After all it no only has a brain in it's head/body but each of it's eight arms/tentacle has brachial and sucker ganglion for each ?pair? of suckers. These ganglion give each sucker a small brain, thus the total brain must be enormous. Certainly this must make the octopus one of the smartest denizens of the ocean?
   
   Now how do we communicate with it?

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2. 2. dythrame 02:26 AM 10/8/10

   Iwould like to mention that your article on octopus made a a gramatical mistake there are no such things as "Octopus's"the plural is Octopi

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3. 3. Neuromancy in reply to dythrame 09:24 AM 10/12/10

   Further, octopuses is an acceptable plural of octopus, and octopi is based on the incorrect assumption that the word is derived from Latin. It actually has Greek roots, and the plural would be octopodes.

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4. 4. Tony Sidaway 10:35 AM 10/12/10

   Wonderful. As a non-biologist I'm delighted to say this is the first time I've seen the word "infundibulum" used outside the pages of Kurt Vonnegut's novels. The reality of this infundibulum (Wikipedia tells me there are more!) and its companion the acetabulum is as amazing as the fantasy.

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5. 5. agenthucky in reply to dythrame 12:13 PM 10/12/10

   Actually, because of the origin of the name, the plural form of octopus is octopods.

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6. 6. hotblack 07:12 PM 10/12/10

   I would only add that I can recall having read these very same posts on at least half a dozen other threads pertaining to Octopus studies, and I would not be surprised if this same conversation is had EVERY time an Octopus-related article comes up.

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7. 7. bulldog. in reply to dythrame 09:05 PM 10/12/10

   its singular. "'s" shows possession. 1st grade material. I think these guys know how to proofread.

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8. 8. Neuromancy in reply to hotblack 04:19 PM 10/14/10

   True, I don't know why I chose that moment to correct someone's grammar...
   
   In order to be constructive, I encourage people to visit the cephalopod neuroscience blog Cephalove
   http://cephalove.southernfriedscience.com/

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