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How many snails are in your garden?

You will need:

  • Small tin of non-lead based white paint
  • Pen and Paper

    Copyright notice

    * Snails can have parasites that can cause harm. If concerned about handling snails either have rubber gloves or run this experiment with cockroaches or similar.



1. Walk through your garden and find 10 garden snails

​2. Place a small dab of paint on their shell. This is harmless to the snail

3. Release the snails at different places in your garden

4. 1 week later, walk around your garden to find some more snails.

5. Use the formula below to work out the approximate number of snails in your garden.

Total population =                   Total number snails marked                             X Total number of snails in new sample group
   Number of snails marked in a new sample group

If you found 20 snails with 5 being marked, this means you have recaptured half of your original group of 10 marked snails.

So the total population must be approximately 40 snails.

This answer is only a good guess, as anything could have happened to the snails over a week!
Be Amazing Book Front Cover; Ben Newsome, teacher & founder of Fizzics Education. Be Amazing -how to teach science the way primary kids love
Be Amazing!
How to teach science, the way primary kids love

Read more about Be Amazing

Mark and recapture is just one technique used by ecologists to count animal populations.

Ecologists study the relationships between animal and plant communities.
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