An octopus can taste something the instant it touches it, before it's near its mouth
Every one of an octopus's hundreds of suckers is packed with chemotactile receptors, a sense found nowhere else in the animal kingdom that lets the arm 'taste' a surface by touching it. In 2020, researchers identified the receptor family responsible, showing it responds to greasy, poorly water-soluble molecules nearly impossible to smell or taste from a distance underwater. It lets an octopus check whether something wedged in a dark crevice is food before bringing it near its mouth.