Caitlin Bloomer found a huge crayfish in Kentucky. A colleague said he had caught bigger ones. This started a search across the country. Scientists listed 20 large crayfish from 18 different types. Bloomer's animal made the list.
The biggest was a Tennessee bottlebrush crayfish in a university collection. Its main body measured 86.6 millimetres. This did not include its tail, claws or feelers. Most of the largest crayfish had bodies about 80 millimetres long.
The team found no clear link between size and place, oxygen or type of home. Their hard shells or muscles may limit growth instead. Scientists need to study this idea more. Some crayfish in other parts of the world grow much bigger.
