Cephalopods, class of marine only animals like octopus, squid, cuttlefish and nautilus are the most developed and well adapted mollusks.
All groups have some common characteristics like:
- jet propulsion type locomotion
- highly developed nervous and sensory system
- ability to rapid color change due to presence of chromatophores (pigment cells)
- highly developed cardiovascular system
- adaptation for raptorial feeding and a carnivorous diet
Caribbean Reef Squid, Bonaire, NA
Squids, octopi, cuttlefish and nautilus differ in habitats, hunting strategies,diet etc.
- Squids are pelagic (free swimming) inhabiting typically open ocean and feed on fish and crustaceans
- Cuttlefish although free swimming, inhabits mostly costal waters and hover not far from sea bed hunting commonly for shrimps and crabs
- Octopi bottom dwelling cephalopods live in dens located in crevices and holes. They make excursions in search of food or lie in wait near the entrances of their lairs. Clams, snails, crustaceans, and fish are seized and dragged into the lair, where they are eaten.
- Chambered Nautilus is pelagic, deep water species rarely seen by divers
Cuttlefish Indian Ocean, South Africa
Reef Octopus hunting for Conch