It's electrical signals that allow the lobes of a venus flytrap to snap shut faster than a frog can flee. In animals, those sort of signals travel via the nervous system, which plants like the flytrap conspicuously lack. In a way, it's like the plants can send email without the Internet. How's it work? Science writer Ferris Jabr explains.
Also, there's this paragraph, which makes you feel very sorry for that frog:
Having secured its meal, the trap begins to eat by releasing an array of digestive enzymes–special proteins that help control the rate of chemical reactions. This acidic concoction dissolves the victim, allowing the Venus flytrap to absorb the nitrogen it can't get from the nutrient-poor soil in which it grows. Around ten days later, the trap reopens, revealing a crumbling exoskeleton.
