Army ant cleaning crew

A little while back, army ants came through the lab clearing and made their way through all the rooms in both the old and new labs. These ants are pretty amazing -- they just appear one day in a steady stream of antiness and go everywhere in search of insects and other food. Anything that crosses their path gets swarmed and devoured...even HUMANS!! No, no, I am kidding, but these ants do give really painful stings so you need to be careful around them. This swarm actually crawled up a wall and attacked a wasp nest under an eave. The wasps had no chance and the ants ate all the larvae in the nest while the adult wasps circled the swarm helplessly.
Army ants are almost constantly on the move, but make temporary "nests" called bivouacs. The bivouac looks like a termite nest (a large brown blob on a tree/vine/liana) but is comprised solely of ants -- a living nest. These ants had their bivouac about 15 meters behind the lab buildings. I took a couple of pictures, but didn't want to get too close -- you also can't breathe on these guys because it makes them very mad and more likely to attack and sting you. The bivouac I saw was approximately 2 meters tall!
Although they may seem scary, these ants are really great at cleaning all the dead/live insects out of houses and offices. I let them do their work in my office (I left for a couple of hours) and hopefully they got rid of all the smaller ants and roaches for me!