Nepenthes: The Most Dangerous Carnivorous Plant

There are a lot of scary-looking and interesting carnivorous plants that can be found in the wilderness. But, what is the most dangerous carnivorous plant? (Can it eat anything as big as a frog or a rat?)

The most “dangerous” carnivorous plant is the Nepenthes pitcher plant which is not dangerous for humans but only for insects, small frogs, and small mammals. Some species of this plant can grow traps up to 41 cm (16 inches) tall and 20 cm (8 inches) wide, with which it can catch animals as big as a rat.

In the rest of this post, I will give you a more in-depth look at different Nepenthes species, where they grow, how they lure and trap animals, and how big the largest animal is they can catch.

The Most Dangerous Carnivorous Plant: Nepenthes

Firstly we have to know that we are on the same page with the world relative. Dangerous is a relative term because carnivorous plants are only dangerous to:

  • Mainly any kind of crawling insects
  • (very unlucky) Flying insects
  • Small mammals like mice, shrews, and in rare cases even rats

The Nepenthes is a genus of carnivorous plants, also known as the tropical pitcher plants or monkey cups. There are about 170 different species of Nepenthes, all with different sizes and slightly different looks.

These plants grow in extreme habitats, where other plants have trouble growing or surviving. They are especially found in South China, Indonesia, Malaysia, the Philippines, Madagascar, Seychelles, Australia, and a couple of other places around the world.

Some of the Nepenthes species grow in wet lowlands, where it’s constantly humid and hot, while the majority of Nepenthes grow on tropical slope forests with warm days but cool to cold and humid nights year-round.

A few species even grow in places with cold days and nights near freezing.

The nepenthes grows big traps that are low to the ground – which makes them so dangerous for mice, shrews, or rats because they can easily access the traps. The Nepenthes also grows in vines climbing up on trees.

Below I have listed a couple of the most dangerous and biggest species.

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Nepenthes rajah 41cm tall, Photo by Gina Hamilton

Other “Dangerous” Nepenthes

Nepenthes rajah

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Nepenthes rajah
Photo by: Ch’ien Lee

This pitcher plant has (dark) red traps with a big leave hanging over the top of the trap. This species of Nepenthes grows naturally on the slopes of mountain Kinabalu and other neighboring mountains within Kinabalu National Park in Sabah, Malaysia on the island of Borneo.

The Nepenthes rajah is the biggest pitcher plant known to man. The traps of this plant can grow up to 41 cm (16 inches) tall and 20 cm (8 inches) wide (see picture above). These traps are capable of holding 3,5 liters of water 2,5 liters of digestive fluids.

With these big traps, the Nepenthes rajah is able to capture animals as big as rats. There have been reports of people finding unlucky birds in the traps but this is a rare treat for the plant.

Nepenthes attenboroughii

Nepenthes attenboroughii
Photo by: Dr. Alastair Robinson

This enormous pitcher plant was only discovered in 2007. One of the largest pitcher plant species in the world. With its size, it could catch and digest animals as big as mice and shrews.

The Nepenthes attenboroughii has big yellow/green/red traps with different color patterns and grows naturally on the highlands of Mount Victoria, a big mountain in central Palawan, the Phillippines.

With traps up to 30 cm (12 inches) tall and 16 cm (6 inches) wide, this species of Nepenthes is one of the largest and also most dangerous carnivorous plants. Also because the traps hang very low to the ground, it is easy for mice, shrews, and rats to be “caught” by the trap.

Nepenthes edwardsiana

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Nepenthes edwardsiana
Photo by: Alastair Robinson

Next on this list is the Nepenthes edwardsiana, this spectacular species is famous for its beautiful and dangerous looks, with knife-edge blades.

This tropical pitcher grows naturally in the highland slopes of Mount Kinabalu and Mount Tambuyukon, Malaysia on the island of Borneo. It has bright red and yellow colors and its elongated traps can grow up to 30 cm (12 inches) tall and 7 cm (2,75 inches) wide.

The traps of this pitcher plant grow amongst shrubs up to 5 m high, but can also grow low on the ground. When they grow low on the ground, it’s more dangerous for mice, small frogs other small insects, and animals to fall into the trap.

What makes these traps so dangerous for small animals is the knife-edge top of the pitcher, which makes it even harder for a trapped animal to climb out of the trap once they fall in.

Other Nepenthes Species

This could be an endless list of different “dangerous” pitcher plants because there are more than 170 different species of Nepenthes. I am going to spare you having to scroll down for an hour.

Many of the other Nepenthes species grow close to the ground with big traps between 20-40 cm (8-16 inches) tall and 10-20 cm (4-8 inches) wide, which makes it very unfortunate for frogs, mice, and shrews…

These traps not only dangerous for mice, shrews, and frogs but also for spiders and other crawling insects.

How they Lures, Trap and Digests Animals

Nepenthes pitcher plants naturally grow on nutrient-poor soils, this is why they have evolved to lure, trap and digest animals to get nutrients they would usually get out of the ground.

However, the Nepenthes doesn’t obtain energy from the insects it traps and digests, only nutrients like nitrogen, phosphorus, and potassium.

So, how does the most dangerous carnivorous plant trap animals?

To Lure…

To lure animals to the trap, the top leaf of the pitcher and the peristome (large thick ring at the top of the pitcher) secretes sweet nectar. The smell and taste of it attract insects and other small animals.

When an insect or other small animal eats off the nectar from the trap, there is a big chance that the animal will slip into the pitfall trap, which has a micro-structured, slippery surface. This surface is also fully wettable and causes insects to slip by aquaplaning on a thin layer of water (see picture below).

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Nepenthes jamban, Photo by Alfindra Primaldhi

To Trap…

Once the animal has slipped into the trap, the trapping can begin. To trap the prey, the inside wall of the trap is lubricated with wax or a thin layer of water. This lubrication makes it very hard for the animal to crawl out of the trap.

Also, the pitcher’s peristome has a ridged entrance to the pitfall trap. The edge on the peristome makes it much easier to move into the pitcher than out, which is what makes the Nepenthes so dangerous for animals once they get trapped.

To Digest…

Once the prey has fallen into the trap, the prey falls in a “dangerous” watery fluid full of digestive enzymes. The prey will eventually drown in the fluid and then slowly get digested by the enzymes and microorganisms living in the fluid. During the digestion of the prey, the plant takes up as many nutrients from its prey as it needs.

If the animal is too big for the trap to digest, the trap will eventually turn brown or black and fall off.

Biggest Animals Caught By Nepenthes

Nepenthes are known to capture animals as big as rats. But these are rare treats for the plant. With the Nepenthes rajah growing traps up to 41 cm tall, it could probably trap animals even bigger than rats. As far as we know that has never happened before.

However, there is still a lot of wildlife to be discovered. Who knows what is possible in the world of carnivorous plants?