Science23 Jun 2009 09:18 pm
On May 31, 2009, 55 pilot whales washed up on Kommetjie beach in Cape Town, South Africa, shortly after daybreak. Relying on earth moving equipment, National Sea Rescue Institute volunteers managed to move 20 of these stranded whales back to the sea, but the remaining whales were too weak to make it back to the water. When it became clear that additional rescue efforts would be in vain, South African law enforcement officials were left with no choice but to euthanize the suffering whales with a gunshot to the head. This mysterious tragedy begs the question: why do an estimated 2000 whales end up beached every year?
For the majority of whales, getting stranded on a beach amounts to a death sentence. Most beached whales end up dying from dehydration, suffocation, infection and/or drowning (their blowholes may become immersed during high tides). At sea, a whale’s massive body is supported by water: on land a whale’s respiratory muscles are unable to fully operate under the weight of its body, which eventually leads to suffocation. Moreover, a beached whale’s blood circulation becomes blocked in the part of its body that is pressed against the ground, causing tissue death. Thus, even if a whale is eventually returned to the water alive, it may die soon thereafter from infection caused by the toxins secreted by the dead tissue.
With respect to lone strandings, scientists have theorized that a solitary whale might inadvertently beach itself if it is sick or hurt. Because whales rely on “sonar” to help them orient themselves, parasites or injury could confuse its normally remarkable sense of direction. Interestingly, only about 10 whale species are frequently involved in mass beachings. Scientists have noted that the common factor across these susceptible species is their tight-knit, group-oriented social organization.
Odontocete whales, such as the sperm whale (the “ferocious” Moby Dick was a member of this species), which live in large and chummy social groups, are the most susceptible to group strandings; solitary species, by their very nature, never beach themselves en masse. As such, it has been hypothesized that these kin-loving whales may accidentally become beached while following a confused leader, or end up stranded in an effort to come to the aid of a fellow whale sending out a distress call. In light of these explanations, one cannot help but think that Melville should have made the blood-thirsty Moby Dick a different type of whale. By the dictates of his species, it is unlikely that Moby would devote his energies towards pulverizing ships and chomping off the limbs of captains….
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