Cephalopod intelligence

An octopus in a zoo

Cephalopod intelligence has an important comparative aspect in our understanding of intelligence, because it relies on a nervous system fundamentally different from that of vertebrates.^[1] The cephalopod class of mollusks, particularly the Coleoidea subclass (cuttlefish, squid and octopuses), are considered the most intelligent invertebrates and an important example of advanced cognitive evolution in animals.

The scope of cephalopod intelligence is controversial, complicated by the challenges of studying these elusive and fundamentally different creatures. Classical conditioning of cephalopods has been reported, and one study (Fiorito and Scotto, 1992) even concluded that octopuses practice observational learning.^[2] However, the latter idea is strongly disputed, and doubt has been shed on some other reported capabilities as well.^[3] In any case, impressive spatial learning capacity, navigational abilities, and predatory techniques remain beyond question.

Examples of intelligence

Predation techniques

Unlike most other mollusks, all cephalopods are active predators (with the possible exception of the bigfin squid). Their requirement to locate and capture their prey has been a probable driving force behind the development of their intelligence, uniquely advanced in their phylum.

The humboldt squid hunts schools of fish, showing extraordinary cooperation and communication in its hunting techniques. This is the first observation of such behaviour in invertebrates.^[4]

Crabs, the staple food source of most octopus species, present significant challenges with their powerful pincers and their potential to exhaust the cephalopod's respiration system from a prolonged pursuit. In the face of these challenges, octopuses will instead seek out lobster traps and steal the prize inside. They are also known to climb aboard fishing boats and hide in the containers that hold dead or dying crabs.^[5]

Dexterity

Dexterity, a trait essential for tool use and manipulation is also found in cephalopods. The highly sensitive suction cups and prehensile arms of octopuses, squid, and cuttlefish are just as effective at holding and manipulating objects as the human hand.^{[citation needed]} However unlike vertebrates the motor skills of octopuses does not seem to depend upon mapping their body within their brains, as the ability to organize complex movements is not thought to be linked to particular arms.^[6]

Octopus opening a container with a screw cap

Communication

Another example of cephalopod intelligence is the communication that takes place between the more social species of squid. Some cephalopods are capable of rapid changes in skin color and pattern through nervous control of chromatophores.^[7] This ability almost certainly evolved primarily for camouflage, but squids use color, patterns, and flashing to communicate with one another in various courtship rituals. Caribbean Reef Squid can send one message via color patterns to a squid on their right, while they send another message to a squid on their left.^[8][9]

Tool use

As of 2009, the octopus is the only invertebrate which has been conclusively shown to use tools. At least four specimens of the Veined Octopus (Amphioctopus marginatus) have been witnessed retrieving discarded coconut shells, manipulating them, and then reassembling them to use as shelter. This discovery was documented in the journal Current Biology and has also been caught on video.^[10][11] Of course many crabs use discarded shells of other species for habitation and others choose items of vegetation to cultivate on their carapaces as camouflage and endless insects use rocks, sand, leaves and so on as building materials but none of this behavior compares to the complexity of the octopus's fortress.

See also

• Animal intelligence
• Dog intelligence
• Cat intelligence

References

External links

• What behavior can we expect of octopuses? by Dr. Jennifer Mather, Department of Psychology and Neuroscience, University of Lethbridge and Roland C. Anderson, The Seattle Aquarium.
• Is the octopus really the invertebrate intellect of the sea? by Doug Stewart. In: National Wildlife. Feb/Mar 1997, vol.35 no.2.
• Giant Octopus — Mighty but Secretive Denizen of the Deep from the Smithsonian National Zoological Park
• Living Fossils Have Long- And Short-term Memory Despite Lacking Brain Structures Of Modern Cephalopods
• M.J. Wells (1962). Brain and Behaviour in Cephalopods. Heinemann. 
• Roger T. Hanlon & John B. Messenger (1996). Cephalopod Behaviour. Cambridge University Press. 
• Marion Nixon and John Z. Young (2003). The Brains and Livees of Cephalopods. Oxford University Press. 
• Binyamin Hochner; Tal Shomrat & Graziano Fiorito (June 1, 2006). "The Octopus: A Model for a Comparative Analysis of the Evolution of Learning and Memory Mechanisms". The Biol. Bull. 210 (210): 308–817. PMID 16801504. http://www.biolbull.org/cgi/content/full/210/3/308. 
• Octopuses are Smart Suckers!? By Dr. Jennifer Mather, Department of Psychology and Neuroscience, University of Lethbridge and Roland C. Anderson, The Seattle Aquarium
• Through the Eye of an Octopus, by Eric Scigliano, Discover Magazine, October 1, 2003.