Cuttlefish are incredible animals in many ways, yet we know so little about them. When we thing of cephalopods, we typically picture octopus, or even squid, yet this animal is equally unique and impressive. It is possibly the most intelligent of the invertebrates; animals that do not possess a backbone. We usually think of invertebrates as being less complex and less intelligent than vertebrates. They are cold blooded and they lack the bone structure that many animals possess. But these animals possess an extremely complex and impressive ability to change their colour and texture to match their surroundings. As a self-defense mechanism, it's brilliant. They blend in perfectly with their surroundings at will. And while we once believed that this was an automatic process that occurred without intention, researchers have found that a cuttlefish can actually change it's appearance for a food reward, even when it contrasts with the environment. This suggests that the cuttlefish exerts more influence on these changes than it once seemed. Cuttlefish have a unique and complex visual system that allows them to detect and process differences in the polarization of light. This allows them to see shades in great detail and provides them with a visual acuity that more than compensates for their inability to detect colours in the usual way. Their "W" shaped pupils and sophisticated ability to focus by manipulating their eye lens allows them to look forward and backward with ease. Their optic nerve position and concentrated areas of receptor cells eliminate the blind spots that all vertebrates have. Their stereopsis, or depth perception is also superior to ours, an extreme advantage in hunting. But most incredibly, the cuttlefish has such well developed eye function, even before birth, that it is able to see its surroundings while it is still in the egg, waiting to hatch. After birth, they are influenced by what they had been able to see from the egg, and food preferences may be affected by their early experience before they hatched. This also shows sophisticated and advanced recognition at an early age. This cuttlefish can be seen using its long and rubbery tentacles to catch a small fish. The two arms shoot out quickly and grasp the fish with their suckers, then pull the fish in to the beak to be eaten. It's rare for this behaviour to be observed as cuttlefish will normally shy away from humans, especially when hunting. It's even more rare to capture an event like this on video. The researcher noticed that two cuttlefish were following him and they made what appeared to be an intentional effort to use the diver's lights for hunting. It is possible that they recognized the distraction that the lights presented, enabling them to sneak up on their prey more easily. At the end of this clip, we also see the colour change that occurred when the rival cuttlefish passed in close proximity. Males will darken their faces, even while contrasting with their surroundings, as a threat display to competitors. As the passing cuttlefish continued farther along, the colours of both reverted to a display that camouflaged them. The underwater world is full of creatures that bear little resemblance to land animals and to ourselves. It would be easy to mistakenly underestimate these animals simply because we do not understand them. We are only beginning to learn about life on the planet that we share.