Predatory Plants

Hey, wait a minute… is that plant eating your gerbil?

FLESH-EATING FLORA
Carnivorous plants developed a taste for flesh over 200 million years of evolution. Here’s how it happened: All over the world, in areas where the soil is low in nutrients (particularly swamps and marshes), some plants had to make up for the nutritional shortfall. So they developed the ability to capture and eat insects, fish, small reptiles, and even the occasional small mammal. Here are some of our favorites.
SNAP TRAPS
These plants have jawlike, hinged leaves that act like a trap. The leaves are lined with rows of fine trigger hairs that, when touched by an insect, cause the lobes of the leaf to close, capturing the prey inside. The two lobes then form a seal to create a temporary “stomach,” where the hapless bug is digested over a couple of weeks. When consumption is complete, the lobes reopen to set another trap. The leaves repeat this cycle three or four times and then become inactive as new leaves sprout and take over.

The best known in the snap-trap category is the Venus flytrap, native to the Carolinas in the United States. Another member of the family, the waterwheel plant (named for its shape), lives in the waters of Europe, Asia, Africa, and Australia.
LOBSTER-POT TRAPS

These predatory plants have a complicated underground leaf chamber that, for microscopic organisms, is easy to enter but impossible to escape. The best example of this category is the corkscrew plant, which has a Y-shaped leaf filled with twisting corridors that lead to a final stomach-like chamber, where tiny protozoan creatures are digested.
PITFALL TRAPS

These grow in the rain forests of South America. The most prominent member of this group is the pitcher plant. Its leaves curl inward, like a piece of paper that’s been rolled into a cone. Insects (and in some cases rodents) climb into the pitcher’s “mouth” only to find they can’t get out. The walls inside are slippery, and the cavity is filled with a liquid that drowns and digests any critter unlucky enough to venture in.
FLYPAPERS
As their name suggests, these plants use sticky stuff— a gluelike substance known as mucilage— to trap their prey. The leaves of the plants are studded with fine glandular tentacles that secrete the mucilage. Once an insect comes into contact with the gumminess, there’s no escape. A trapped bug eventually dies from asphyxiation or the exhaustion of flailing around trying to free itself.

The most widely distributed flypaper plant is the sundew, which includes almost 200 species across every continent except Antarctica. Their beautiful glistening leaves make them a favorite ornamental plant, though they’re difficult to keep alive in a home garden— no matter how many bugs you feed them.
Another flypaper plant is the butterwort, which produces an antibacterial enzyme that prevents its captured prey from rotting during digestion. Hundreds of years ago, farmers in northern Europe started using this enzyme to heal sores and wounds on their cattle. Butterwort is also used in Norway to make tjukkmjølk, a thick curdled milk.
SUCTION TRAPS

These come in just one variety: the bladderwort. But more than 200 species of bladderwort grow in either water or wet soil and can survive almost anywhere fresh water can be found. The plants feature bladders that pump out liquid, which in turn creates a vacuum whereby prey, mainly insects, are sucked in through a sort of trapdoor on the bladder. (Larger species of bladderwort are big enough to capture and digest fish and tadpoles.) Scientists consider the suction trap one of the most sophisticated structures in the plant kingdom.