Deafness may be the main reason.
SARASOTA - Dolphins are beautiful creatures, but mysterious, and perhaps no mystery is greater than why each year a small number of dolphins beach themselves, usually fatally.
Now a Mote Marine scientist thinks he has found at least part of the answer: Deaf dolphins.
Randy Wells, who helped author a study about dolphin strandings, said most dolphins that beach themselves have at least partial hearing loss.
The answer isn't as surprising as it seems, Wells said.
My answer to the centuries-old mystery of why whales and dolphins beach themselves can be stated in only one word: BAROSINUSITIS
ReplyDeleteBarosinusitis in diving mammals is a pressure related injury in the sinuses and air sacs of their head. The physical trauma is induced by rapid and excessive
changes in ambient water pressure. Such pressure oscillations occur above the epicenter of certain shallow-focused undersea earthquakes. But not all
quakes generate whale-dangerous seismic waves; only those events that happen in specific places and in a specific manner are dangerous to diving whales.
The sinuses and air sacs of toothed whales serve as acoustic mirrors reflecting sound inside their heads in such a fashion to enable their echo-navigation
system to function properly. An injury in this critical part of their biosonar system disrupts echo-navigation, causing the animals to lose their normally
excellent sense of direction. It also prevents them from diving and feeding themselves.
Some injured pods recover with a week or so while others are washed into a beach before recovery occurs.
Sharks sense the whales are in trouble, move in close, and wait for the opportunity to snatch any weakened pod member that falls behind.
Injured, trailed by hungry sharks, and unable to navigate or dive, the wounded whales and dolphins huddle together in a tight group and swim downstream
with the flow of the surface currents.
The reason non-navigating whales always swim downstream is because there is increased resistance to swimming in any direction except downstream. This
increased resistance turns their streamlined bodies and keeps them pointed in the same direction as the flow of the surface currents.
Land masses that extend out to sea opposing the flow serve to trap sand, flotsam, and whales swimming with the flow.
Besides undersea earthquakes, naval sonar, oil industry airgun arrays, and underwater explosives can also induce barosinusitis.
Capt. David Williams, President
Deafwhale Society, Inc.
(a 501-c non-profit whale research corporation)