A Carnivorous plant can be defined as a plant that encompasses three basic characteristics:

1. It must be capable of capturing prey
2. It must be able to digest the prey it catches
3. It must benefit from the nutrients it absorbs from the prey.

(1-3 from Barry Rice, The Carnivorous Plant FAQ) The prey of carnivorous plants is typically insects or small aquatic animals however there have been reports of carnivorous plants digesting frogs, birds, and rodents. These reports are very rare and usually occur with the larger species of carnivorous plants, such as the tropical Pitcher plant. In case you’re wondering if plants capable of digesting animals such as rodents and birds are also capable of digesting humans, I’m afraid I’ll have to put your Little Shop of Horrors thoughts to rest. As far as I know, there is no possible way for the carnivorous plant’s enzymes to digest live human flesh (or even harm it for that matter). Tests have been done on dead human tissue in very small  doses but all in all these plants present virtually no risk to humans (although, if you do happen to fall into a giant carnivorous plant, I would have to suggest exiting as soon as possible.)

There are five basic trapping mechanisms found in carnivorous plants. These mechanisms include:

Pitfall traps: Pitfall traps essentially involve luring the prey inside the plant whose insides form a pit.  Once the prey enters the plant it usually slips on the slick walls of the pit; falling to the bottom where it drowns in a watery substance pooled at the base. Depending on the species of plant the fluid could be water or perhaps a fluid produced by the plant itself.  Once the prey is dead, the plant then digests the carcass using digestive enzymes.

Cool video that explains how the Pitcher Plant utilizes the Pitfall trap mechanism.

Fly paper traps: This trap involves sticky leaves which are caused by the plant’s tiny glands that produce a mucus like substance.  Many times the gooey substance produced by the glands will resemble dew drops or nectar which helps in attracting prey to the leaves. Once the unsuspecting prey touches the leaves it sticks to the plant and is eventually digested; either by enzymes or bugs that share a symbiotic relationship with the plant.

This video was taken by a person who came across the ‘Butterwort’ plant; a plant that uses the ‘Flay paper’ mechanism to capture lots of tiny insects. (note: The camera person touches the bugs which is kind of gross but other than that it’s a pretty cool video.)

Snap traps: This is probably the most commonly known type of trap since the Venus Fly Trap (or Dionaea muscipula) utilizes this trap to capture (you guessed it) flies or other small insects. Basically, the plant’s mouth is made from two leaf lobes that are spread apart when the trap is ready to snap. Once the prey ventures onto the lobes, tiny hairs on the trap walls pick up the prey’s movements, alerting the plant to snap shut. Once shut, the lobes create an inescapable enclosure where the prey will then be digested by the plant’s enzymes.

This video demonstrates the sensitivity of the Venus fly trap. Notice how quickly the lobes snap shut!

Suction traps: Sometimes called ‘bladder traps’, these traps work underwater using a small pouch which sucks the prey into an inescapable entrapment. When setting the trap the plant drains the water from the pouch, creating a puckered look. Once an unsuspecting creature swims close enough to the deflated pouch, the plant than opens the entrance and floods the pouch with water; creature included.  A trap door keeps the creature from escaping and the plant then releases its digestive enzymes.

Minute 1:25 is where the narrator points out some ‘Bladderworts’ which utilize the  suction or ‘bladder trap’ mechanism. Unfortunately I wasn’t able to find a video that shows the bladder trap in action.

Lobster-pot traps: These traps are not unlike the Pitfall traps in that both traps lure their prey into an enclosed are where they are eventually digested. However, Lobster-pot-traps are much more inviting to their prey. This is because these traps usually give off a strong scent of nectar or are internally illuminated; fooling the bug into thinking that it is investigating a safe food source. Then, either by the promise of nectar or inward pointing bristles, the prey is than lead to the stomach where it is digested.

This video provides a close look at the Cobra Lily; a plant that utilizes the Lobster-pot trap. Note the close up of the ‘windows’ which help illuminate the inside of the plant. This video also covers the Butterwort!

To conclude, Carnivorous plants are quite elusive in nature and appearance; many appearing to be your everyday plant adorned with colorful and inviting flowers. However, once getting to know this funny little irony of the botanical world, it’s clear that there’s much more to this plant than just a pretty face.

Want to know more? I found these sites to be very helpful while writing this article:

• http://www.carnivorousplants.org/ru
• http://www.botany.org/Carnivorous_Plants/
• http://www.sarracenia.com/faq.html