Two pilot whales lay stranded on a beach in New Zealand. Picture credit: Bahnfrend - CC0
Last year New Zealand experienced its largest stranding in decades. More than 600 pilot whales hit the shores of New Zealand’s South Island in February. The country has the highest stranding rate in the world, counting around 90 strandings per year.
Mass strandings in one location are unusual and often draw immediate help from rescue teams. According to Stephen Marsh, Operations Manager at British Divers Marine Life Rescue, the primary cause for a group stranding is due to the great cohesion between these mammals: “Pilot and sperm whales have very strong social bonds between each other. If one of them is unhealthy or has a problem, their request for help can push the rest of the whales to follow the disorientated animal, who will eventually lead the whole group to the shore”.
However, cases of healthy whales stranding have been confusing biologist and scientists for a long time. This uncertainty has resulted in the diffusion of several, unreliable theories to try and explain this event. A common belief is that these mammals are committing suicide.
Truth is, that while people tend to associate whale strandings with whales dying, their behavior can actually be a survival strategy.
Scott Baker, Professor at the Marine Mammal Institute of Oregon, studies the evolutionary and ecological pattern and process in whales and dolphins. He suggests an interesting point of view to explain this specific form of whale stranding:
“The public is not aware that if a whale is ill, or has an incapacity, most of the times, it will sink. The reason why they move to the shore is actually to stay alive, to save themselves. Suicide is costly for the animal and its evolution, and it is not in whale or dolphin culture to do this”.
To know more about the truth behind whale strandings, buy Fauna’s March issue!
Rosa Farsetti