When a single whale or dolphin strands itself on a beach, it is usually very sick. When those animals strand themselves in groups, however, other, unknown factors are probably at play.
There are several theories as to why groups of whales will sometimes swim onto beaches around the world. One is that because whales are such highly social creatures, the healthy individuals refuse to abandon a sick or injured fellow pod member and then follow it into the shallow water. Some researchers believe that a disturbance in the Earth’s magnetic field causes an error in the cetaceans’ navigational skills. Other scientists suggest something like mass panic.
Group strandings of dolphins are far less common than those of whales. But just such an event occurred at Arraial do Cabo, Brazil, at 8:00 a.m. on March 5, 2012. Gerd Traue captured the event on film.
Luckily for these dolphins on that day, beachgoers were willing to give a helping hand.