Yes, octopuses are intelligent:

Brain size: Octopuses have large brains relative to their body size, with about as many neurons as a dog.

Brain structure: About two-thirds of an octopus's neurons are in its arms, not its head.

Learning: Octopuses can learn by watching other octopuses, and they can retain information for several months.

Problem-solving: Octopuses can solve problems, navigate mazes, and untie knots.

Tool use: Octopuses can use tools to build dens, create shields, and collect coconut shells.

Escape artists: Octopuses are known to escape from tight spaces, including aquariums.

Camouflage: Octopuses can quickly learn how to hide and camouflage themselves.

Intelligence: Octopuses are intelligent in ways that are different from human intelligence:

They can learn to attack one of two objects based on characteristics like color, shape, texture, or taste.

They can generalize, applying a previously learned rule to new objects.

They can use conditional discrimination, modifying their choice depending on the context.

They can use spatial learning to find hidden shelters.

Intelligence genes: Octopuses have genes that are active in the vertical lobe of their brain, which is analogous to the human hippocampus.