The water scorpion is one of Britain’s most intriguing pond insects. With its flattened, leaf-like body and pincer-like forelegs, it’s perfectly adapted for ambush.
This stealthy hunter breathes through a snorkel-like tail and thrives in still, weedy freshwater habitats.
It may have a scary-sounding name (and appearance to match) but the water scorpion doesn't sting humans – though it can deliver a nip if handled without care.
What is a water scorpion?
The water scorpion (Nepa cinerea) is a freshwater insect with a flattened, brown, leaf-shaped body and pincer-like front legs, which it uses to catch prey. Despite the name, it’s not a true scorpion.
How big are they?
Adults grow to around 2–3cm long, with an additional 2cm breathing tube at the rear, which it uses like a snorkel.
Can water scorpions sting you?
They can’t sting humans – the tail, which looks like that of a scorpion, is actually a harmless breathing tube. If handled carelessly, water scorpions may deliver a little bite, but it's not very painful for humans.
Where do they live?
Common and widespread throughout lowland Britain, water scorpions favour still or slow-moving waters – such as garden ponds, lakes and canals – especially those with plenty of vegetation.
What do they eat?
Water scorpions prey on aquatic insects, tadpoles and small crustaceans.
How do they hunt?
As ambush predators, they cling to underwater plants or hide among leaves, waiting motionless until prey passes within reach – then they strike swiftly with their powerful forelegs.
Top image: water scorpion. Credit: Getty
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