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What is a Snap Trap?

If you ever wonder how carnivorous plants get their food, here is an in-depth look at how these carnivorous plants eat, what they eat and where they live.

This is a close look at a carnivorous snap trap plant.

Alright, what you are about to read may possibly be one of the strangest descriptions of plant life that you have ever come across. I had never heard of a Waterwheel plant before researching this, and my life will never be the same going forward.

5 Types of Carnivorous Plants and How They Trap gives a brief overview of different trapping methods. There you can read about the pitfall trap, flypaper trap, suction trap, and lobster pot trap. You’re likely to already know about the Venus Fly Trap which is infamous for its use of snap trapping,  but today we’re going to look at a species that is much less widely known; the Waterwheel. The best way to describe what snap trapping is is through its most allusive user.

Related: Pitfall Trap | Flypaper Trap | Bladderwort | Corkscrew Plants | Thank You Flowers

Waterwheel: Aquatically Carnivorous

Aldrovanda Vesiculosa

So it’s already known that most carnivorous plants don’t develop a root system, since they don’t actually obtain any nutrients from the soil. The same concept goes for this aquatic carnivorous plant. The Waterwheel is entirely free-floating and due to its shape, it’s actually capable of movement in the water.

This is a close look at a venus flytrap.

Since Waterwheels are so rare, photos of them are extremely limited. This is the same mechanism displayed in a Venus Fly Trap.

The Waterwheel’s stem is surrounded by whorls, which are leaves that grow in concentric circles along the length of the stem. The traps exist on each of the leaves, are about 3mm wide, and are shaped like a mouth of sorts. The traps are lined with fine hairs, that when aroused, triggers the snapping mechanism of the trap.

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Inside the mouth will be a mucus layer of digestive enzymes that will slowly digest whatever happened to land in the Waterwheels mouth.


  • a central free-floating stem surrounded by whorls
  • of traps, groups of 5-9
  • the trap is capable of closing within 10-20 milliseconds! (isn’t that nuts???)
  • grows to be about 40 cm long

Where They Live

It’s rather mind-boggling, but there are only 50 confirmed Waterwheels in existence. This puts them on the critically endangered list.

Waterwheels prefer shallow, warm, standing water that is low in nutrients. They like lots and lots of sunlight. They are endemic (meaning they occur in these areas alone) to Asia, Europe, and Africa. That being said, they are very sparse within these continents, since there’s only 50 of them left.

A woman harvesting Lotus flowers.

A pretty cool fact about how they spread: the Waterwheel is slightly sticky, not for the purpose of trapping, but so that they stick to the feet of birds. Why? This is how they spread their genes. They are carried wherever the bird goes, and so Waterwheels tend to exist only along the migratory path of certain birds.

What They Eat

Since the Waterwheel is smaller than some carnivorous plants, its main diet is small aquatic invertebrates and protozoans.

This is a close look at a bunch of zooplanktons.


How does a snap trap work?

The snap trap works like a mouth chomping on a chip. If someone ran a salty potato chip along your lips, you would want to eat it. Snap traps are like open mouths coated with sensitive hairs, they when brushed, trigger the jaw to shut.

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Why are carnivorous plants carnivorous?

It’s a very bizarre method of adapting to low nutrient environments. An ingenious way of access nutrients that other plants do not have the means to do.

How does the waterwheel carnivorous plant survive?

It survives by feeding off of protozoans and small invertebrates in the water. They get caught in its snap trap and promptly digested.

Can a Waterwheel be a house plant?

Almost certainly not. There are barely enough that exist in nature that it is very unlikely that anyone who wasn’t searching for one like it was their job, would ever manage to find one.