It’s well established that cephalopods like octopuses and squids are vastly smart animals, rivaling the intelligence of most mammals, yet to what extent the mollusk’s mental capacities extend are hotly debated. But a recent study looking into the intelligence of cuttlefish has found that not only can they count, their ability to do so is better than a one-year-old human.
In a series of experiments, researchers from the National Tsing Hua University in Taiwan were able to show that the ingenious invertebrates showed a consistent preference for larger quantities of shrimp, showing that they have what is termed “number sense.” This may seem fairly obvious, but the team then found that the one-month-old cephalopods were able to tell the difference between groups containing four shrimp and five shrimp, whereas human one-year-olds can only tell the difference between one and two items, and two and three items, but no higher.
Not only that, but the cuttlefish took longer to decide which group of shrimp to go for when the choice was between larger numbers of prey. This makes the researchers suspect that rather than just using quick visual cues to judge which box contained more shrimp, the cephalopods were physically counting the number of shrimps in each group before then making up their mind which one to go for.
It also turns out that the clever cuttlefish are also pretty shrewd, choosing quality over quantity. The decision-making process was not as simple as "always go for the larger number", with the cuttlefish valuing some foods more than others. For example, when offered the choice between one live shrimp or two dead ones, they almost always went for the live offering, suggesting that the mollusks are more of a discerning customer.
The researchers also found that the invertebrates' appetite also had a role to play, as when the cuttlefish were presented with the choice between one large shrimp or two smaller ones, their choice depended on their level of hunger. When the cephalopods' stomach was rumbling, they opted for the one large prey item, but when it was already full, they chose instead the two smaller ones. To explain this, the researchers think that the invertebrates may become more risk adverse when hungry, as “attacking one small prey in a group is less risky than capturing one large lone prey for the cuttlefish.”
Already deemed one of the smartest of the cephalopod bunch, this latest series of experiments propels the cuttlefish even higher in the intelligence ranking, making them “at least equivalent to infants and primates in terms of number sense.” Maybe you should think again before tucking into that calamari.