835 false killer whales swam ashore under their own power in Argentina in 1946 and became the largest mass stranding of any single whale species in recorded history.  What could cause so many whales to voluntarily commit suicide in this way?

Harsh weather, disease, geomagnetic field misalignment, and even sonar interference have all been proposed causes of these strandings but none of these are seen in every case and in many cases none of them are observed.  It is almost as if these animals are partaking in some cult-like mass suicide as they are often so adamant about dying that they will even fight rescuers and return to the shore after they have been moved back to sea.

One common factor is that the species that are commonly communally beached are highly social.  It is a wonder how such behavior would have evolved through natural selection but it seems that these species are so dependent on each other and have such a strong bond that they follow each other even to death.