Neptune notwithstanding, beached whales are baffling

In a heartbreaking scene that made national news last week, 22 pilot whales died off Florida’s Everglades National Park when they got stranded in shallow water. The other 29 members of the pod floundering near shore disappeared after rescuers tried guiding them back to sea.

No one knows whether the living whales returned safely to the open ocean or if they died and got recycled by sharks and other marine scavengers.

Nor does anyone know why pilot whales, many young and seemingly healthy, sometimes beach themselves.

With all the gloomy stories we hear about oil spills, global warming and pollution, it would be easy to blame the whales’ plight on human activity. But while some of those factors may play a part in modern standings, pilot whales swimming to their deaths on beaches is not a new phenomenon.

Around 350 B.C. Aristotle wrote about beached whales (species unknown, but pilot whales, the species most commonly stranded, are found in the Mediterranean): "It is not known why they sometimes run aground on the seashore: for it is asserted that this happens rather frequently when the fancy takes them and without any apparent reason."

Ancient Romans believed that grounding was Neptune’s punishment to whales that behaved badly.

Whether naughty or nice, pods of pilot whales and other species, such as sperm whales, have likely been swimming to their deaths in the shallows since whales have been in the sea, about 50 million years. And not because it strikes their fancy. There’s a reason it happens. We just don’t know what it is.

That’s not for lack of trying. Researchers have been studying pilot whale carcasses for decades, and although no one knows why entire pods of the 13- to 18-foot-long whales occasionally end up on beaches, scientists have theories.

The most probable is that the whales’ navigation system malfunctions. This might be from a viral or bacterial disease that infects the pod, heavy metal pollutants, an undersea earthquake, magnetic field anomalies, unusually warm or cold oceanic currents, getting lost while fleeing predators or chasing prey, or some combination of these. Or none of the above. Research is ongoing.

There is, however, some good news. A 2012 study showed that five Australian pilot whales guided back to sea after stranding survived. This suggests that although not all individuals in a pod can be saved, some can.

Mass strandings of marine mammals touch our hearts, moving a wide variety of officials and volunteers to launch rescue attempts. It’s good to know that some of those efforts succeed.

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Reach Susan Scott at www.susanscott.net.