What Animal Sudoku is
Animal Sudoku is ordinary sudoku with the digits painted over. Instead of writing a 1, you place a cat; instead of a 3, a fish. Nothing about the puzzle changes — the same grid, the same single solution, the same "one of each, everywhere" rule. Only the alphabet is different.
That matters more than it sounds. In a number sudoku, a child who is still shaky on digits spends part of their attention decoding the symbols and only the rest on the actual thinking. Animals cost nothing to read. A four-year-old who has never written a number can look at a row, notice the frog is missing, and put it in — and that is genuinely the whole skill sudoku is made of.
This page holds three grids at once. The tabs above the board switch between a 4×4 with four animals, a 6×6 with six, and a 9×9 with all nine, and each size keeps its own puzzle saved separately, so moving up and coming back never loses your place.
Meet the nine animals
The nine animals were picked so that no two are easy to confuse. Each one has both its own outline and its own colour, which means a child can tell them apart by shape if colours are hard for them, or by colour if they are scanning quickly. Look at the fish and the turtle: different colours, but also completely different silhouettes.
- 🐱 Cat — orange, pointed ears and whiskers. Animal number one, so it appears in every grid size.
- 🐸 Frog — green, with its eyes sitting up on top of its head.
- 🐟 Fish — blue, the only animal that points sideways instead of facing you.
- 🐝 Bee — yellow with dark stripes and pale wings.
- 🦉 Owl — purple, with two big round eyes and pointed ear tufts. Joins at 6×6.
- 🐢 Turtle — teal, a low dome of a shell with its head poking out to the right.
- 🐘 Elephant — grey, wide ears and a curling trunk. Joins at 9×9.
- 🐼 Panda — a white face with dark ears and dark eye patches.
- 🐞 Ladybird — red with black spots and a dark head.
One rule, said three ways
There is really only one rule in sudoku: no animal may appear twice in the same group. What changes is what counts as a group — and there are three kinds.
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Every row
A row runs across the board. Each row holds every animal exactly once, so if you can see the cat somewhere along a row, no other square in that row can be a cat.
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Every column
A column runs top to bottom. Same deal: each animal appears once, no repeats.
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Every box
The thick black lines mark the boxes, and the box shape changes with the grid size: 2×2 squares on the 4×4 board, wide 2×3 rectangles on the 6×6 board, and the familiar 3×3 squares on the 9×9 board.
Solving your first square
Most squares are not solved by staring at the empty square. They are solved by looking at everything around it and crossing animals off until one is left. Here is that idea on a 4×4 board, with the square we are solving marked with a question mark.
- 1. Row 1 already has the frog and the bee, so the ? has to be the cat or the fish.
- 2. Column 1 already has a fish, and no animal repeats in a column — so the ? is not a fish.
- One animal is left. The ? is the cat.
The row already contains a frog and a bee, so the question mark can only be a cat or a fish — those are the two animals the row still needs. Now turn the same trick sideways: the column below already contains a fish. A fish cannot appear twice in one column, so the question mark is not a fish. That leaves exactly one animal.
The box gives the same answer, which is worth checking on purpose: the top-left box holds the frog, the fish and, once you fill it, everything but the cat. Two different routes to the same square is not wasted effort — it is how you build the habit of proving a placement instead of guessing at it.
Which grid size to start on
- 4×4 — sixteen squares and four animals. A first puzzle usually takes a couple of minutes, and every deduction is a short one. This is the size to sit next to a small child for.
- 6×6 — thirty-six squares and six animals, with those wide 2×3 boxes. The jump from 4×4 is bigger than it looks, because for the first time you cannot hold the whole board in your head at once.
- 9×9 — the full-size grid with all nine animals. This is a real sudoku, not a warm-up: a comfortable solve here means the same puzzle with digits will be comfortable too.
If a size feels frustrating rather than interesting, drop back one and finish two or three puzzles there first. Nothing is lost — each size keeps its own saved game. The same three sizes exist as number grids too, if a child would rather practise digits: 4×4 sudoku, 6×6 sudoku and classic 9×9 sudoku.
Tricks that work better with pictures
Some sudoku habits are actually easier with animals than with digits, because your eye can filter by colour and shape faster than it can read.
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The roll call
Pick a row and name all the animals it should have, in pad order: cat, frog, fish, bee. Whichever names you did not say are the ones still missing. This works far better out loud than in your head.
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The one-animal sweep
Choose a single animal — the ladybird, say — and hunt only for that one across the whole board. Ignore everything else. Because each animal has its own colour, this sweep is quick, and it often shows you a row or box where the ladybird has only one square left to go.
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Start where it is crowded
The fullest box, row or column is always the easiest place to find your next move, because there are fewer animals left to choose between. Empty corners of the board can wait.
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Mark the maybes
Tap Notes and then tap animals to leave tiny marks in a square — the ones that might belong there. Auto Notes fills those marks in everywhere at once, and any square that ends up with a single tiny animal in it is solved.
These are the same techniques adult solvers use, only wearing fur. If you want the number-grid versions written out properly, we have a guide to beginner sudoku strategies and one on how pencil marks work.
For grown-ups
What a child practises here is not arithmetic — there is none in sudoku, animal or otherwise. It is constraint reasoning: holding several rules in mind at once and using them to rule possibilities out. That is the same move behind "it can’t be Tuesday, because we do swimming on Tuesday", and it transfers well beyond puzzles.
Animal Sudoku is also unusually good for playing together, because the two jobs split cleanly. An adult or older sibling can run the roll call out loud — "this row still needs the owl and the turtle" — while the younger player does the looking and the tapping. Nobody has to hand over the tablet for that to work.
Practical notes: progress saves in the browser for each grid size, so a puzzle abandoned at bedtime is still there in the morning. Mistakes are counted but never punished, there is no timer counting down, and nothing on this page needs an account.
Other picture sudokus to try
If the animal grid goes down well, the same idea comes in other costumes: Shape Sudoku uses six geometric shapes, Color Sudoku uses six colour swatches with no drawing at all, and Space Sudoku swaps in rockets and planets. All three are 6×6 boards with difficulty levels, so they are a good next step after the 6×6 animals.
For a child who is starting to read, Wordoku sits neatly between pictures and numbers: it is played with letters, and solving it spells a hidden word down the diagonal.