Sad News, Dolphins Get Alzheimer’s Disease, Too

It turns out that dolphins are susceptible to Alzheimer’s Disease, and I’m not crying, you’re crying.

Dolphins, like humans, can live long after having offspring—a benefit that may be linked to Alzheimer’s Disease.Scientists from the US and UK found signs of the chronic neurodegenerative disease in the brains of dolphins that died after washing up on the Spanish coast.

“It is very rare to find signs of full-blown Alzheimer’s Disease in non-human brains,” Simon Lovestone, a researcher in Oxford University’s department of psychiatry, said in a statement.

“This is the first time anyone has found clear evidence of the protein plaques and tangles associated with Alzheimer’s Disease in the brain of a wild animal,” he added.

And the news is heartbreaking.

The aquatic mammals—with their streamlined bodies and flippers, a keen sense of hearing, and social behaviors—have long played a role in human culture. From Greek myths to SeaWorld, everyone loves a well-trained cetacean.

It was bad enough learning about the tragic captive life of Tilikum in Blackfish. Now you’re telling me these beautiful creatures suffer short-term memory loss, problems with language, disorientation, mood swings, and loss of motivation?

“Non-human animals have so much to tell us about dementia, not just as ‘models’ for Alzheimer’s Disease in people, but also to improve our understanding of dementia in these animals,” study co-author Danièlle Gunn-Moore, of the University of Edinburgh and the Roslin Institute, said.

The team—team—hailing from the Universities of St. Andrews and Edinburgh (in Scotland), Oxford (in England), and Florida (go Gators!)—analyzed certain “plaques and tangles” (abnormal clusters and twisted strands of protein) in the brains of dolphins.

Their results, published in the journal Alzheimer’s and Dementia, point to an unexpected culprit: insulin.

The hormone regulates blood-sugar levels, creating a complex chemical reaction known as insulin signaling. In humans—as in dolphins and orcas—that process has evolved to prolong our lifespan beyond the fertile years. But it also leaves us exposed to diabetes and Alzheimer’s Disease.

“If we are right, then it is already too late, by tens of thousands of years,” Lovestone said, discouragingly. “That’s about how long ago in our evolution we are likely to have acquired the insulin resistance that gained the extended lifespan that calorie restriction would produce.”

Without studying wild dolphins, scientists cannot identify whether older dolphins experience the same memory problems and confusion we see among human patients.

This understanding, however, may lead to better drugs and an eventual cure for Alzheimer’s Disease.

The full paper, “Alzheimer’s disease in humans and other animals: A consequence of postreproductive lifespan and longevity rather than aging,” is available online