"This is the additional weekly image thread for the Nature Forum. While images posted to this thread should still be nature in theme, it may contain a small amount of human-made objects and therefore less restricted than the Monday in Nature threads. Please see this discussion for more details: Alternative weekly thread in Nature forum Each participant please post no more than just one image per weekly thread." It's fall here in Uruguay. These caterpillars seem to be moving together to find a good place to pupate since they don't appear to be feeding. We have seen about 6 of these masses over the last few years. This is one of the smaller ones. It is quite a sight to see this jet back mass moving. I haven't been able to ID them, so any suggestions are most welcome. The good news is that the daylight hours will start to increase in about 2 weeks.