Many naturalists become so familiar with the animals they study that they can recognise individuals within a population using just their shapes and patterns. If that's too difficult, animals can be ringed or tagged. These tricks give scientists the invaluable ability to track the fates of individuals, but try using them on octopuses.
Recognising shape and pattern is impossible when your subject has the ability to change the texture and colour of its already pliant body on a whim. Injured individuals are distinctive enough, but only for a short while before their remarkable healing abilities close wounds and regenerate arms. Tags, which work well for closely related animals like squid, are useless for octopuses, which have eight long and dextrous arms for pulling markers off. And other techniques are simply either too impractical, expensive, or harmful to the creature.
This inability to track individuals in the wild has severely limited ...
