Are you scared of going to the forest because you think there are man-eating tigers in the forest? What would you do if there were man-eating plants too?

Don’t worry. Man-eating plants do not exist. But insect and animal-eating plants do. They are what you would call non-vegetarian plants.

In fact, there are 500 varieties of plant species that trap prey and eat it. The most famous among these carnivorous plants are sundews, pitcher plants, bladderworts and the Venus flytrap.

These plants are found in places with an acidic soil that lacks nutrients essential for the plant to make food.

Actually it is not as if these plants cannot survive without being non-vegetarian. Like other plants, they also use light, carbon dioxide and water to make their food. But, without non-vegetarian components in their diet, they will lose strength and become easy victims of predators. They might even lose the fight for survival as their competitors take over.

Why are Some Plants Non-vegetarian?
Why are Some Plants Non-vegetarian? [Illustration by Shridevi R.]
Most of these plants have worked out complex ways to catch their prey. The pitcher plant’s leaves are shaped like pitchers and a part of the leaf forms the lid. The mouth of the pitcher secretes a sweet-smelling substance, which tempts insects to the trapdoor. Once they step on to the threshold, they are tempted to move further to hunt for the source of the nectar. That proves to be the fatal step for them as they lose their grip on the slippery slope and fall into the pitcher. Some pitchers are big enough to kill small mammals, scorpions and reptiles. Nepenthes rajah, a species in Borneo, has pitchers, which are up to 35 cm long and 18 cm wide — large enough to trap a small rat.

Although the sundews also use a sticky substance like the pitcher plant to attract their victims, they use a more active device to catch them. They have tentacles that close in on the prey the moment it lands on the leaf.

The Venus flytrap’s leaves have fine hairs-like structures that are sensitive to touch. When an insect touches the trigger hairs, the leaf folds along its midrib, closing with such speed that the victim cannot escape.

The bladderwort, which lives in water, uses something similar to a mousetrap to get its food. Its trap, which looks like a bladder, is sealed to maintain a partial vacuum and has a trapdoor entrance. The trapdoor has fine trigger hairs that are sensitive to movement. The bladderworts also use a sticky solution of mucus and sugar as bait. When an animal gets attracted by the sugary solution, it brushes against the trigger hairs, and the trapdoor flies open and the bladder sucks in water because of the partial vacuum in it. The victim is swept inside helplessly along with the water and the trapdoor closes on it. All of this happens in ten to fifteen thousandths of a second, so fast that human eyes may not be able to take in the action.

After the victim has been trapped, the plant uses either bacteria or enzymes to absorb its nutrients.

You will be surprised to know that it is not only plants that are carnivorous. Some fungi also have similar eating habits. The genus Dactylella is one of them. It strangles eelworms. It has threads known as hyphae, which form loops and when a worm puts its head or tail into the loop, the noose tightens. The fungus then sends out other hyphae to eat the corpse.