Animal collective behavior reveals itself in often-mesmerizing visual displays of swarming insects, flocks of birds in flight, and schools of fish pulsating underwater as a single unit. Now, researchers report they’ve found a possible reason for a peculiar display of collective behavior from fish shoals in sulfur springs in Mexico: deterring predators. The results appeared yesterday (December 22) in Current Biology.
Study author and Leibniz Institute of Freshwater Ecology and Inland Fisheries behavioral ecologist Juliane Lukas explains to The Scientist that sulfur mollies (Poecilia sulphuraria) gather in large shoals at the surface of the low-oxygen springs to avoid hypoxia. There, they’re ripe for the picking by predators such as kingfishers, kiskadees, and other birds. When presented with a threatening stimulus, these “carpets of fish,” as Lukas describes them, repeatedly disturb the water in a wave-like fashion by diving down for a few seconds, triggering their neighbors to mimic their diving ...
