Cuttlefish have a genuine sense of numbers, according to Chinese researchers at the National Tsing Hua University.
The cephalopods, part of the family which includes squid and octopuses, can discriminate between different numbers of shrimp.
The researchers also found that cuttlefish can weigh up size over quantity. When they are hungry, they prefer the larger when faced with the choice of a couple of small shrimp or just one big one.
But when they’ve already eaten, they choose the two smaller prey.
“These results demonstrate that cuttlefish are capable of number discrimination and that their choice of prey number depends on the quality of the prey and on their appetite state,” the researchers write in the paper published by the Royal Society.
The authors say this result is similar to economic decision-making in humans.