If you live in Southern Louisiana, chances are you have been to a crawfish boil.

Crawfish boils are a tradition that are passed down through families with each having their own unique customs, recipes, and etiquette. Some things are constant throughout nearly all boils, however, including what is considered the gospel truth among Louisianans: Never eat the straight-tail crawfish.

One of the first things you learn at a crawfish boil is do not eat the straight-tail crawfish. Supposedly, straight tail crawfish were dead before the boil and are therefore not safe to eat. This bit of advice has been passed down from generation to generation, and it’s one of the most popular myths about crawfish.

Why do crawfish curl when cooked? The abdomen of crustaceans, such as crawfish, usually curls as a result of muscle contraction when cooked. Therefore, the assumption is if their abdomens are decaying or decomposed in any way, it could prevent the muscle from contracting. However, research done by the LSU AgCenter has shown there is no difference in tail curl between crawfish that were alive when boiled and ones who were already dead. The researchers determined the straight tail was most likely a result of putting too many crawfish in the pot at once.

There’s a better way to test if the crawfish is truly edible. If the meat is mushy or crumbles, don’t eat it. Otherwise it should be fine to eat, regardless of the tail curl.