These prawns are so hungry, it makes them smarter

When you think of prawns, probably the first word that comes into your head isn't "innovative". "Tasty", perhaps, or "fiddly" if you're not a fan of seafood.

Steamed prawns, or shrimps, as they are commonly known in America

The latest research does not show that prawns are secretly creative geniuses – far from it – but it does show that they can innovate in their own way. More importantly, it reveals the sorts of circumstances that trigger them to do it.

The giant tiger prawn, an important species for aquaculture

While the consensus among the scientific community is that necessity drives innovation, researchers in the UK wanted to find out how desperation and changing circumstances will force an animal to innovate more deeply.

Prawns were picked for this study as it is a species that encounter radically different environments depending on context. Prawns spend much of the year in rock pools on the shoreline. These pools vary enormously in size and in how much food they contain. At times when you go and look in a rock pool you might find 20 prawns or just a single prawn. This changeable environment might force prawns to try new behaviours.

Rock pool

The researchers collected common prawns and grass prawns, and placed them in water tanks. At the other end of the tank was a piece of food for them to find. In some cases the food was behind a barrier with a single hole in it, forcing the prawns to take a roundabout route. In others, it was under a small box that the prawn had to move.

Common prawn

The team tracked whether or not the prawns attempted these novel behaviours, in a range of setups. Prawns were either large or small. Sometimes they were alone, in others they were in a group of 16. Sometimes the prawns were hungry, sometimes they were full.

Most prawns live in fairly shallow waters and use their "walking legs" to perch on the sea bottom

The conclusion? Generally, it's the guys who are worse off who are innovating and there are two big factors that could be important: size and hunger.

Small prawns might be unable to muscle their way past competitors, so might instead find creative ways to get to food. Meanwhile, hungry prawns have an obvious incentive. In line with that, hungry prawns often turned the box over to get food. Some of them also pulled bits of food out through holes in the box.

Tanks in a prawn hatchery – farmed prawns are usually fed pellets, made mainly from fish

Overall, both size and hunger drove the prawns to innovate to get food, but only under certain circumstances. Said the head researcher,

"The headline message is that which one is important depends on context. If you're on your own, size is important. Small prawns tended to innovate. If you're in a group, size doesn't seem to matter and it's really hunger that drives it."

(All images - credit: Wikimedia Commons under Creative Commons licence)