Shrimp and Prawns are both types of invertebrate, meaning they have no backbone and use a hard outer shell to protect them and keep their bodies enclosed.
Shrimps and prawns are also both considered to be Crustaceans (from the Latin root crustaceus, "having a crust or shell,"). Crustaceans are a subgroup of invertebrates which share the characteristics of a hard outer shell, or exoskeleton, segmented bodies, and paired appendages (arms and legs).
Both shrimp and prawns grow via a process known as molting, or ecdysis, in which the outer shell is removed and then replaced with a new one whenever the animal begins a growth cycle.
Decapoda imagery courtesy of Wikipedia Commons and Ernst Haekel.
Shrimp and Prawns can be found throughout the world, in both fresh and salt water conditions. Both are opportunistic scavengers, meaning they generally eat what can be stirred up off the sea or pond bottom.Their early diet includes zooplankton, phytoplankton and algae, and dead organic materials. Later in life, both types of decapod scavenge some dead and some living organic material, such as decaying plants, fish, clams, and even other shrimp.
Both groups use special chemosensory antennae structures located on the tops of their heads to help them detect the chemical signature of food particles and to help them locate them.
The reason that a lot of people have trouble differentiating between this organisms has to do with the prevalence of the use of the common names, "shrimp" and "prawn". The terms have been used interchangeably in many fishing communities, as the similarities between these organisms are very obvious, and to the common eye, the differences are pretty minor.
In the United Kingdom, Australia, and other primarily English speaking countries, "Prawn" is used to refer to either shrimp or prawns, whereas in the United States and Canada, the word "Shrimp" is used more commonly for both.
This is why science nerds worldwide use latin names when communicating, to ensure they really are talking about the same organisms.
Prawns are defined as a group of similar species which make up the suborder Dendrobranchiata. In one way, you could categorize them as the larger shrimp. It is thought that perhaps the term "prawn" came from a need to differentiate larger species from smaller ones. Both terms originated in Great Britain, although if you asked a fisherman there, the definition of what a shrimp vs a prawn would be is often highly individual.
Biologically, Dendrobranchiata share a couple of key physiological differences. Prawns have a series of overlapping plates on their abdomen, each overlapping easily over a single other plate.Prawns also have three sets of feeding arms, or maxillipeds. ​ Although the tail, or telson, of a prawn often bends inwards towards the central carapace in a smooth, "C" shape, prawns lack the distinct Caridean angular bend in the plates of the abdomen.
Some species of prawn are highly sensitive to light, an often bury themselves under the seafloor during the day, only to emerge and migrate to the surface to feed on microorganisms at night time.
Prawns can live 3-6 years. Each prawn spawning event creates up to 100,000 young, which is less impressive when compared with the number of young a shrimp can produce. Prawns also require that the female prawn has recently undergone a molting process in order to begin reproduction. The hard outer shell of the female prawn has to have been removed for the male to be able to properly transfer his sperm package to the female, and for her to properly fertilize the eggs. Once fertilized, the eggs are immediately released into the water column, and left to drift and settle on their own before continuing through the development cycle.
​Shrimp are a part of a suborder of crustaceans known as the Plyoceyemata, and an infraorder (smaller grouping) known as the Caridea. They have two pairs of feeding claws (also known as maxillipeds). One set of their feeding claws has a pair of pincers on it for cutting and holding their prey.
You can tell a shrimp from a prawn by looking at the second segment of their abdomen, which overlaps with the first and third segments of the central area of the body. Shrimp are generally small (0.25-5 centimetres in length), and have a distinct structural characteristic, known as the Caridean bend, in their abdomen, their lower digestive and reproductive area.
If you're really looking at a specimen in detail, you could open up their respiratory system to look at their gills-the organ these animals use to remove oxygen from the water around them and use it to metabolize their food. Shrimp have what's known as lamellar gills. These gills are dinner plate-like in structure, and lie just inside the entrance of the cardiac section of the carapace. Shrimp have specialized appendages that can actually fit perfectly between the lamellar gills and can be used to brush parasites and fouling organisms from the gills- just like your toothbrush removes plaque from your teeth!
Shrimp are known as broadcast spawners, meaning that when they reproduce, they make thousands of young at a time. For protection, the female shrimp will carry her fertilized eggs with her for the initial stages of their development by holding them to her body using a pair of legs known as pleopods. A female shrimp can have up to 1 million eggs in a single reproductive season!
Most shrimp live 8 months to 3 years, depending on the species and geographical distribution, but in confined conditions, shrimp have been known to live up to 20 years.
So there you have it! If you're having a nice seafood dinner in Wales, UK, it might be prawns on your plate, but the same meal could be a shrimp dish in Vancouver, BC!
Stay tuned to learn more about how shrimp and prawns are harvested, farmed and brought to your dinner table!
Diffen.com. "Prawn vs. Shrimp". Accessed online November 2, 2017.
Shaikh, F. July 26, 2017. "Prawn vs Shrimp: Know the Difference between Shrimp and Prawn." Foodsforbetterhealth.com. Accessed November 5, 2017.
Haekel, E. Kunstformen der Natur (1904), plate 86: Decapoda.
Watson, M. October 23, 2017. "What's the Difference between Shrimp and Prawns?" The spruce.com. Accessed online November 7, 2017.
Zwicky, A. November 11, 2011. "Rock Shrimp". Accessed online, November 17, 2017.