Whales are the largest animal inhabiting the earth, weighing up to 170 tonnes. When they beach themselves, they get dehydrated and crush themselves to death by the sheer weight of their own bodies. What possibly causes these disastrous incidents?
There are several types of strandings. A single whale’s stranding may be caused by illness, injury or old age. They are too weak to swim against the current and the tide eventually washes them ashore. On the other hand, there are mass strandings of the same species of whales. Species such as pilot whales and sperm whales use sonar for navigation. When the beach is wide and very gently sloping, the shoreline may be not detected by their sonar pulse reflections. Whales are social animals and swim in pods. When the dominant whale fails to detect the coastline, it heads onto the beach and the rest of the pod may follow the disoriented leader onto shore.
There are also multiple-species strandings when different species of marine mammals beach themselves at the same time and in the same place. This may even include dolphins. Probably they all die from the same cause. Researchers have been studying possible causes of this phenomenon. One explanation is that pods of whales may venture too close to the beach when hunting for food or fleeing to avoid predators. They become helplessly trapped by receding tides and many of them end up beaching themselves to death.
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