Cephalopods The Intelligent Invertebrates www.imms.org The Institute for Marine Mammal Studies (IMMS) is a non-profit organization established in 1984 for the purpose of public education, conservation, and research of marine mam- mals and sea turtles in the wild and under hu- man care. Located in Gulfport, MS, IMMS has been an active participant in the National Stranding Network since its inception. IMMS is the premiere organization in the Mississippi- Louisiana-Alabama sub-region of the Gulf Coast with the capability and experience to care for sick and injured marine mammals and sea turtles. Additionally, IMMS promotes public awareness of marine conservation issues through its involvement in the community. Institute for Marine Mammal Studies P.O. Box 207, Gulfport, MS 39502 Phone 228-896-9182 Fax: 228-896-9183 Email: [email protected] Website: www.imms.org Cephalopod Quick Facts Octopuses, squids, cuttlefish, and nautiluses are all cephalopods. Cephalopods are mollusks and are related to snails, slugs, clams, mussels, and oysters. Cephalopods have lived in the Earth’s oceanic basins for more than 500 million years, and were dominant predators millions of years before fish appeared. Nautiluses are the only cephalopod with external shells; squids and cuttlefish have internal shells; and octopuses have none at all. Octopuses, squids, and cuttlefish have three hearts, and their blood is blue when exposed to air. The nervous system of cephalopods is the most complex of the invertebrates and their brain is lo- cated in a capsule around their throats. Octopuses have a toxin to neutralize their prey but only two types can kill humans with their toxin (some blue ring species and O. mototi). REMEMBER Prepared by Mike Mashburn, 2012 References Dr J.B. Wood’s Cephalopod Page: www.thecephalopodpage.org The Octopus News Magazine Online: www.tonmo.com Laboratory of Robert Hanlon: www.mbl.edu/mrc/hanlon/ Unless otherwise noted all images in this publication were obtained from: http://commons.wikimedia.org The second is the release of one or more com- pact, mucus-bound clouds close to the size of the cephalopod intended to confuse the preda- tor as to which is the real animal; this behavior may also be accompanied by the cephalopod changing color or “blanching.” Cephalopods are fast-moving hunters that de- pend on vision to locate prey, detect predators, and communicate with one another. The cepha- lopod eye is probably the most sophisticated of all the inverte- brates and is as complex as the vertebrate eye; as such it is an often cited example of convergent evolution. Like vertebrates, coleoid eyes contain an iris, pupil, and lens but not necessarily a cornea. Among coleoids squid have round pupils, while those of octopus are rectangular and the cuttlefish’s is W-shaped. The eyes of the nauti- loids are less sophisticated than other cephalo- pods; lacking a lens they have a small opening that acts like a “pin-hole” camera. Somewhat paradoxically, the feature that makes the coleoids excellent visual communi- cators also makes them unchallenged masters of camouflage. They have the ability to rapidly and precisely vary the color, patterning and texture of their skin. This is possible through fine-motor control of projections on the skin called papillae, and pigment-containing and light-reflecting cells (chromatophores) located at, or directly under, the skin’s surface. This control is so precise that some squid have been observed “double signaling,” using half their body to communicate with an animal on that side while sending a completely different sig- nal to a receiver on the other side. Intelligence Cephalopods, and in particular octopuses, are generally considered to be the most intelligent of the invertebrates, but even so assessment of their intelligence remains controversial. What is clear is that cephalopods have the most complex brains of any invertebrate, enclosed in a carti- laginous brain capsule and surrounding the throat, it contains about 40 lobes and “up to” 300 million neurons (information processing nerve cells). However, cephalopod nervous sys- tems are not strongly centralized in the way that vertebrates’ are; for instance octopuses’ nervous systems have about 500 million neurons but two-thirds are located in the nerve cords of the arms and the arms exhibit significant autonomy even when disconnected from the brain. Scientists studying octopuses have found indica- tions of intelligence in their ability to recognize shapes and patterns, to learn simple mazes, and to use landmarks for navigation while hunting. One study even appeared to document that octo- puses engage in play behavior when given an object to manipulate in an otherwise non- stimulating environment. In the wild octopuses have been observed to engage in planning and tool use in the collection, transport, and assem- bly of items like coconut and clam shells to cre- ate shelters. Much work still needs to be accomplished to assess the degree and nature of cephalopod in- telligence, but it is apparent that these ancient and unique animals will continue to fascinate scientists and lay-persons alike for the foreseea- ble future. This brochure is funded with qualiϐied outer continental shelf oil and gas revenues by the Coastal Impact Assistance Program, United States Fish and Wildlife Service, U.S. Department of the Interior through a grant award to the Mississippi Department of Marine Resources. Phylum: Mollusca