These fearsome insects have large scissor-like jaws called "mandibles", which they use to slice their prey apart. There are over 200 species of army ants. All of these species have one common characteristic - they do not have a permanent nest - instead, they are constantly on the march. Did you know that a single colony of army ants can eat up 500,000 prey animals per day? Nothing stops these predators. Some think that if you measure the weight of all army ants in this world, it would be equal to the weight of every single person on the planet added up altogether.