There are many different types of crustaceans – lobsters, crabs, even woodlice. But one of the most common is the shrimp. There are over 4,000 different species of true, 10-legged shrimp and 15,000 others that we call shrimp, though they’re only distantly related.
With such a wide variety of species, shrimp come many guises. But all ‘true’ shrimp have several characteristics in common. Like lobsters and crabs, they have 10 legs. Their bodies are divided into 2 sections – the head and the thorax – and protected by a hard shell known as a carapace.
They also have another means of protection – a beak-like mouth called a rostrum. This extends from the head and they use it to help steer themselves when swimming. But its main function is to take in food. Quite a versatile organ to have!
Shrimp feed on tiny particles of plant or animal matter which they filter from the water. The vast majority of their food is algae and plankton so you might think of them as little dustmen, cleaning up our oceans and rivers.
Shrimp live all over the world, from Antarctica to the tropics. And they live in a host of different habitats from rivers and estuaries to coasts and coral reefs. Some even dwell in the ocean depths, 5 kilometres below the surface. Down there the water pressure is so great it would crush a submarine like a tin can – but the humble shrimp can take it!
Shrimp live in social groups. For such small creatures (most are less than 4 centimetres long) the advantages of this are obvious. Just like herds of zebra, or any other prey animal, there’s safety in numbers. They even communicate to one another, using snapping and clicking sounds. Perhaps this is to warn the group of approaching danger.
Shrimp are eaten by hundreds of other animals, from fish to whales. But their worst predator is us humans. 2% of all fish caught are shrimp and we eat about 7 million tonnes of them every year. That’s the same weight as 1.5 million elephants! You might think that you’ve never eaten shrimp. If you’ve ever had a prawn cocktail then you have. You see, prawns are just large shrimp. In the USA there’s no such thing as prawns. They simply call them ‘big shrimp’.
There are many dangers faced by shrimp. Overfishing, water pollution and habitat loss have all made shrimp rarer and their conservation status is now ‘Threatened’. That’s not good because, if shrimp do die out, the consequences will be much graver than having to do without a prawn cocktail. Dolphins, whales and countless other species rely on shrimp in order to live. If we wipe out shrimp then we’ll have to say goodbye to many more of the ocean’s creatures. Wouldn’t that be a tragedy?