An Arm That Can Taste

Reach out and touch something, and you feel its shape and texture. An octopus reaching out does something stranger: it tastes what it touches, instantly, through hundreds of suckers lining each arm.

Scientists recently discovered that octopus suckers contain special receptors unlike anything found in other animals, built to sense chemicals that do not dissolve in water. This lets an octopus slide an arm into a dark crack in the rocks and immediately know what is hiding there, food, danger, or nothing at all, without needing to see it or pull it out first.

It is a completely different way of experiencing the world, touch and taste combined into a single sense, spread across eight independent arms. For an octopus hunting in total darkness, that combination might be more useful than eyes ever could be.