Over at the California Academy of Sciences in San Francisco, the Steinhart Aquarium biologists say that it's not enough to keep octopuses fed and healthy. The highly-intelligent cephalopods get unhappy if they don't have things to do with their minds.
As you can see in this insanely cute video from the aquarium, there are many ways to keep octopuses engaged. Biologists give them toys and puzzles — the animals are especially fond of unscrewing jars to get at food inside. Though octopuses are generally not social animals, many studies have offered compelling evidence for their cleverness: They use tools; they can extemporize brilliantly when trying to hide; and a recent paper even suggests that they engage in warfare. Also, in a cool alien detail, they have distributed intelligence. Octopus arms can think independently of each other.
It's hard for humans to admit that other animals might be as smart as we are. But at least at Cal Academy, the biologists understand that octopuses are so intelligent that caring for them means keeping their brains as busy as their bodies.