Each year when salmon swim upstream to spawn, bears and other predators gather to eat them. Also during the annual wildebeest migration, crocodiles gather to feast on the wildebeest as they cross the Mara River in great numbers. There are other examples of where animals gather to hunt at a particular annual event.
Is the information that wildebeest will be crossing the river at a particular time of the year learnt by young crocodiles from older ones, or is it a genetically programmed behavior whereby day length, temperature etc triggers the behavior of the crocodiles? It is easier to imagine that this behavior might be learned in bears, but not so easy to imagine it in crocodiles, though perhaps I am being ‘mammal-centric’.
