Dolphins are known as very intelligent animals. Well, mystery envelops where many of them, even whole groups, like 'suicides' stranded helplessly on the beach. What's the explanation?
But new research suggests a bleak explanation, namely that the strandings were likely because their group leader had dementia.
In research published in the European Journal of Neuroscience, researchers examined the brains of 22 dolphins that washed ashore in Scotland and found that four of them displayed signs of Alzheimer's similar to those seen in human patients.
Most prominent among the signs is the presence of so-called amyloid-beta plaques, which are believed to cause or at least contribute to the lethal symptoms of Alzheimer's and are so far poorly understood.
"This is a significant finding showing, for the first time, that the brain pathology of stranding dolphins is similar to that of humans with Alzheimer's disease," said Mark Dagleish, a University of Glasgow pathologist who led the study.
In humans, Alzheimer's causes significant deterioration of cognitive function, impairing speech, memory, recognition of loved ones, and the ability to perform basic tasks. But Dagleish warns against simply comparing human and dolphin symptoms.
"While it is tempting to speculate that they may also suffer cognitive deficits related to Alzheimer's disease in humans, more research must be conducted to better understand what is really going on," he said.
Nevertheless, the findings lend credence to the theory that because dolphins are social animals, their group was led to death by a leader who had lost his memory.
