Prawns and shrimp look alike and taste very similar, so many people use the terms interchangeably, often referring to smaller examples as shrimp and larger ones as prawns, says Craig Collins, farm manager of Desert Sweet Shrimp.
But prawns can be small and shrimp can be big. The best way to tell the difference is to check out the animal’s abdomen before it’s been peeled or deveined, says Darlene Crist, media relations representative for the Census of Marine Life. Take a look at the underside of the tail and pay careful attention to the second plate. On a shrimp the second plate overlaps both the first and third plates, but on a prawn the second plate will only overlap the third plate.
Though both prawns and shrimp are crustaceans belonging to the Decapoda order, they are members of different suborders: Prawns belong to the Dendrobranchiata suborder, and shrimp to the Pleocyemata. In addition to the slight variation in appearance, their reproductive patterns differ.