We know about the high-profile marine animals, like sharks, dolphins and whales. But the cuttlefish, for all its amazing capabilities, gets little love from people. And that's shame, as it's a fascinating and intelligent animal.
More than 120 species of cuttlefish call Earth's waters home. In fact, they can be found in virtually all oceans, although they do tend to migrate to deep areas during the winter before returning to shallow waters and reefs in spring and summer to mate. They're identified by their eight short arms and two longer tentacles.
Some people might confuse cuttlefish with squid or octopus, since all belong to the class of mollusks called cephalopods (which means "head foot," – these creatures' arms encircle their heads). They differ from other mollusks like snails in that they have no hard outer shell. Cephalopods have been around for about 500 million years, much longer than most other marine life, including fish, and they're some of the smartest animals in the sea. And in this group of smart animals, the cuttlefish stands out for its intelligence. Here are seven reasons why.
1. They're Masters of Camouflage
Like the chameleon, cuttlefish can change their color and texture to blend into their surroundings. But that's not the half of it: Researchers have found that they can "freeze" their camouflage palette by locking hundreds of tiny structures in their skin in place for up to an hour. All this without consuming any energy from their main nervous system to stay in place. This trick allows them to hold their disguise for long periods to avoid being detected – or eaten. This skill also helps them snatch their own prey by allowing them to remain almost invisible as they wait for fish and crustaceans to come by.
2. Cuttlefish Can Count
Math skills are always handy to have! A 2016 study placed 54 different pharaoh cuttlefish (Sepia pharaonis) in a tank, along with a transparent two-chambered box. Each side of the box contained a different quantity of shrimp to eat, forcing the cuttlefish to choose the better deal of the two. Researchers changed the shrimp ratio each time and even played around with larger and dead shrimp to see how those conditions factored into the cuttlefish's decision-making.
The researchers found that the creatures had no problem picking larger quantities of shrimp over smaller quantities. But they could also choose the richer shrimp chamber even in cases of narrow ratios, such as four shrimp in one chamber versus five in the other.
3. Their Ink Is Useful
Speaking of ink, cuttlefish ink – which they squirt at predators — was once used for writing and drawing! In fact, the ink color name "sepia" was taken from the cuttlefish's species name, Sepia officinalis. Nowadays, people mainly use the ink for cooking – it's a key part of some pasta and seafood dishes.
4. Cuttlefish Are Not Afraid to Brawl
Any cuttlefish who comes for another's mate or otherwise angers him should be prepared to for a faceful of ink and some pretty vicious fighting maneuvers. Scientists have long known that cuttlefish are capable of aggressive behavior, but 2011 footage captured this behavior in the wild, rather than the laboratory.
In the footage, a male and female cuttlefish have just finished mating. Another male tries to steal her away. He succeeds at first but then the first male follows them for a while before striking back. The two males start fighting, flashing ink, biting and showing other types of angry-cuttlefish behavior. This is thrilling because it confirms that the aggressive behavior was based on mutual assessment rather than self-assessment when applying game theory models. So, the cuttlefish didn't determine its actions based on only its own strength, but also on considering the capabilities of its sparring partner, too. That takes a bit more thought than simply throwing brawn around. Further, this discovery might prove to be a valuable way to learn more about the cognition and aggression of other animals.
5. They Have a Hidden Weapon
Underneath the cuttlefish's many tentacles lies a razor-sharp beak, much like that of your average parrot. This tool allows the cuttlefish to nosh on crab, mollusks and other hard-shelled animals. The hidden weapon is extra vicious because it sports a toxin designed to freeze prey in their tracks once bitten.
6. They Can Gender Bend
The big, brawny males usually win the lady cuttlefish, but every once in a while, a small male gets his chance. He does this by splitting his colors to show typically "female patterns" on the side of his body facing a larger male while showing his "masculine" side to the female of his choice. Then he sidles up to her and commences mating before the other male has figured it out.
7. They're Shockingly Lazy — For a Good Reason
Cuttlefish spend about 95 percent of their time resting. Although this seems like a major about-face for a species that can be so aggressive, it's actually a smart maneuver. Cuttlefish only live a couple of years at most, but they grow rapidly (up to about 23 pounds or 10.5 kilograms), so too much activity means they don't grow to their full potential. Hence the seemingly excessive down-time.