An octopus can settle onto a rock and match it, the color of it and the roughness of it, in about a second. As far as anyone can tell, it cannot see color at all. That gap is what the book is about.
Four researchers spend a stretch of days in the water off Moorea, in French Polynesia, looking for wild octopuses and trying to work out what is going on inside one. Scientists in the Field books are photojournalism. Real researchers, photographed doing the actual work, in the actual place, with the actual gear.
Which makes this a strange fit for a shelf called Stealth Science, and that is worth saying out loud rather than pretending otherwise. Nothing is hidden here. The science is the subject. It sits on the shelf anyway, for what it teaches sideways: what the job is. The waiting, the empty days, the money, and the specific tools.
The science it actually teaches
Start with the body, because the body is the argument.
An octopus has three hearts. Two push blood through the gills and one pushes it around the rest of the animal, and the blood is blue because it carries oxygen on copper rather than on iron. The main heart stops beating while the animal jets away. That is why an octopus, given a choice, walks.
Then the nervous system, which is where the book earns the eleven dollars. Most of an octopus's neurons are not in its brain. They are in its arms. An arm can taste what it touches, work out what to do with it, and do it, with the central brain giving something closer to a general instruction than a command. Your child has spent their whole life assuming a brain is one lump in one place, in charge. This animal is not built that way, and the book makes that concrete instead of cute.
The skin is next. Color comes from chromatophores, which are sacs of pigment with muscles around them, pulled open and let shut. Under those sit layers that bounce and scatter light, and the whole surface can be roughened into bumps to match a texture. The animal running all of that is, by every test anyone has managed, colorblind. The book does not paper over that. It says the question is open and gives you the leading idea, which is that the skin itself may sense light. That is what an unsolved problem looks like written down honestly, and a child almost never gets to see one.
The method is the other half. Finding an octopus at all is the hard part, and the way you know one is living under a particular rock is the rubbish outside the door: crab claws, drilled shells, the leftovers of meals. A pile of shells is a diet record you can count. That is real fieldwork, and it costs nothing but knowing where to look.
There is also work on personality, which sounds soft and is not. Run the same test on the same animal twice and the bold ones stay bold and the shy ones stay shy. Individuals differ in ways that hold up, and that is measurable rather than sentimental.
Last, the fact that reframes everything above it. Most octopuses live a year or two. They breed once. A female stops feeding while she guards her eggs and dies around the time they hatch, so no octopus has ever met its mother. Whatever this intelligence is, nobody taught it, nobody passed it down, and it grew on a branch of life that split off from ours a very long way back.
A child who finishes this can tell you why "is an octopus as smart as a dog" is the wrong question, and what a better one would be.
The child it lands with
Somebody in your house has already asked whether animals think and got an answer that did not hold up. This is for that one.
Sentences are not hard at ten. The ideas are harder than the sentences, which is exactly the right way round for a strong reader who has run out of ocean fact books and wants something that treats them as capable of a real argument.
This is also a photograph book. A child who reads with their eyes first will get through it on the pictures and pick up the text on the way back.
One place to stop and talk
The arms are the place to break off.
Before you go on, have your child write down what "intelligent" means. One sentence, on paper, so it cannot be quietly edited later. Then finish the book and read the sentence again.
Most definitions a person writes down turn out to be a description of a human. An animal that tastes with its skin, thinks partly in its limbs, and dies at two without ever meeting a parent breaks that definition rather than fitting inside it. Working out what to do with a definition that broke is most of what science is.
What to know going in
This is a gentle book by the standards of the shelf, and there are three things to know anyway.
Hunting is described plainly. An octopus drills through a shell, injects saliva that starts to break the animal down inside its own armor, and eats it out. Some children think that is the best thing they have ever read and some put the book down.
Death is here and it is not violent. A mother octopus stops eating, guards her eggs, and dies. A child who has just spent a hundred pages deciding this animal has a mind will feel that ending, and it is worth being in the room for.
The practical one: the book creates a want. If your child asks for a pet octopus, the answer is no, and not because you are being difficult. They live a year or two, they escape any tank that is not sealed, they need cold clean salt water and real money, and most sold as pets die within months. Tide pools are the honest substitute, and they are free.
Where to get it
$11.99 in paperback at The Octopus Scientists. Of everything on the Stealth Science shelf, this is the one to hand a child who asks big questions rather than one who collects facts. Buy it before the aquarium trip rather than after. It changes what your child stands there and watches, and forty minutes at one tank beats a lap of the whole building.
If your child liked this one
Books we have written about that sit close to this one, by reading level and by subject.
The Quest for the Tree Kangaroo: What the Job Costs
The Quest for the Tree Kangaroo: An Expedition to the Cloud Forest of New Guinea by Sy Montgomery
Grade 5 to 8
Emi and the Rhino Scientist: How One Calf Happened
Emi and the Rhino Scientist by Mary Kay Carson
Grade 5 to 8
Science Comics Sharks: The Science and the Caution
Science Comics: Sharks: Nature's Perfect Hunter by Joe Flood
Grade 4 to 8
Who Really Killed Cock Robin? A Food Web as a Suspect List
Who Really Killed Cock Robin?: An Ecological Mystery by Jean Craighead George
Grade 4 to 7
Browse every book we have written about by age, by kind of book and by subject: Find the right book for your child. Or see the whole Stealth Science shelf.
