These molluscs are really smart and quite alien.
A team of scientists led by the University of Cambridge has found that when cuttlefish know they’re getting shrimp for dinner, they’ll only have a light lunch of crabs. This ability to anticipate their favorite food is an indication of the cephalopod’s complex brain and cognitive abilities.
The Cambridge team fed cuttlefish in different ways. In one experiment, the tentacled mollusks were fed crabs during the day and then shrimp in the evening on a regular basis. In a second experiment, they were fed crab during the day and randomly fed shrimp in the evening. This way, in the first experiment, the cuttlefish could predict that they would be fed shrimp, but couldn’t when the special appeared at random in the second.
According to the team, when the cuttlefish knew they were getting shrimp for dinner, they wouldn’t eat many crabs during the day, but when they couldn’t anticipate their preferred meal, they filled up on crab. Not only that, but when the feeding routines were changed, the cuttlefish quickly learned and adapted. In this way, the animals could make sure they were well-fed, yet not miss out on a treat if they knew it was on the menu.
https://newatlas.com/science/cuttlefish-eat-light-lunch-shrimp-dinner/