Curious Kids: How long would garden snails live if they were not eaten by another animal?

Curious Kids is a series for children. If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.edu.au You might also like the podcast Imagine This, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.

I would like to know how long garden snails would live if they were not eaten by birds (or other predators)? – Alice, age 6, Canberra.

That’s a really good question! There have been reports of at least one snail living as many as 14 years in captivity. His name was George and he lived in Hawaii, in the United States.

Very few people have ever had the patience to study how long garden snails live in the wild. However, it might be longer than we might at first think – studies showed that snails in gardens in California needed to be between two and four years old before they were old enough to have babies. Many of these Californian garden snails, which were studied for almost five years, were therefore over six years old at least – older than you, Alice! It seems that rats and small mammals were the main predators of these snails.

Read more: Curious Kids: why do we have fingernails and toenails?

Counting snail shell rings

There is a snail very like the garden snail that is called the Roman or Apple snail – it is the one that some people like to eat.

A study of a population of these snails in England was able to work out how old these snails are. That’s because, as they get older, you can count growth rings at the edge of their shell.

Some of the snails were at least six years old and probably more like eight or nine. The older snails had very thick shells and were often out and about. The scientists thought this might be because as the snails got older and bigger, fewer birds and other predators could crack their thick shells, and so they felt safe enough not hide away all the time.

So, it seems that if you are a snail that can survive long enough to get big then you might stand a good chance of getting even older – maybe 15 years old. It depends on what type of snail you are.

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Bill Bateman does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.