One of the more dramatic plant movements is the snapping shut of the leaf of a Venus Flytrap when it detects movement on its surface. This one is fast enough to be seen without the need for time-lapse. In fact, it is so fast that slow-motion video is needed to see the details that occur faster than our eyes can handle. The trap of the Venus Flytrap is a highly modified leaf. The upper surface of the flytrap leaf contain 3 hair cells on each half. These are the mechano-motion detectors and are extremely sensitive to mechanical stimuli. As seen in this real-time video, other parts of the leaf fail to elicit a response but when the hair cells are touched 2 times in succession, the leaf slams shut on the chance that a living insect might be caught. By closing in response to 2 closely-spaced stimuli, the plant can avoid closing it's trap when something, like a small twig, happens to fall from above. Carnivorous plants like the Venus Flytrap secrete enzymes that will digest the insect and provide the plant with Nitrogen that it needs for growth.