Octopuses, squids, cuttlefishes, and nautiluses are among the most beautiful animals on earth, and they have evolved large brains, keen senses, and complex behaviors that rival those of fishes and birds. They possess a very special quality known as Rapid Adaptive Coloration. That is, most of them can change their skin patterning and overall appearance in a fraction of a second to help deploy a wide range of adaptive behaviors such as camouflage, alarm, threat, predator escape, and mate attraction.
To accomplish these visual illusions, they have developed elegant skin pigments and reflectors (or bioluminescent photophores) that produce colorful and jewel-like body patterns—each pattern tuned to a specific function and ocean viewer.#4738•
WHY A BOOK ON CEPHALOPODS?
Cephalopods are considered a charismatic animal group due to their colorful appearances, complex behaviors, and overall strangeness compared with most other animals. Some are huge (the giant squid) and some are very small and poisonous (blue-ringed octopus). Cephalopods occupy many oceanic niches and in some cases their numbers are massive—consider that sperm whales feed almost exclusively on squids, and that their biomass alone is estimated by some to equal the total biomass of all human fisheries.
Most cephalopod species occupy a central position in ocean food chains, being a primary food source for many marine mammals (whales, dolphins, seals), birds (penguins, petrels), and a vast array of fishes (including swordfishes, groupers, snappers, barracudas, eels).
They are an ideal meal because they have few or no hard parts and are almost entirely muscle protein; indeed the cephalopods themselves are the subject of targeted fisheries worldwide.
They are totally unlike any other animal group—invertebrate or vertebrate—and are worthy of scientific study in their own right.
The public find them fascinating and weird, or simply like to eat them as a basic protein source.#4752•
"Marine molluscs on steroids" might be one glib way to describe cephalopods, yet this jocular analogy may be more truth than fiction since cephalopods have hormones that tend to super-charge some of their critical behaviors, such as male–male cuttlefish fights when they compete for a female mate#4742•