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What’s a Cat Parasite Doing in a Beluga Whale?
As global temperatures warm, diseases are on the move—sometimes even crossing from the warm tropics to the frigid Arctic.

Climate change has not been kind to the loveable beluga whale. The Arctic ice that it relies on to escape from predators (think polar bears and orcas) is melting. And as if losing your only hiding place isn’t bad enough, belugas now have to contend with another climate-related challenge—a parasite carried by cats.

Normally Toxoplasma gondii makes its home in cat poop (hey, don’t judge). The single-celled microbe can cause “kitty litter disease” in humans, which results in flu-like symptoms), and has turned up in sea otters off the California coast and dolphins in Italy.

But inside an Arctic beluga? That one sure surprised scientists. Last month Michael Grigg and Stephen Raverty, researchers from the University of British Columbia, announced that 10 percent of the belugas living in icy waters off Western Alaska now carry T. gondii, the first time it has been found in the whales during 14 years of sampling.

“It’s strange,” says Kathy Burek, a veterinary pathologist who works with Arctic mammals, “because cats have never been popular house pets in the far north.” But that could be changing as Arctic regions warm, making them more hospitable for cats (and making cats more appealing to humans, thanks to their ability to help control pests). So far, there’s no good study looking into whether house cats are all the rage up north. “We’re still trying to figure that part out,” says Raverty.

But even if cats are still a rarity north of the Arctic Circle, scientists say there’s another way the parasite could be reaching whales: ice—or lack thereof.

Ice serves as an ecological barrier, isolating and protecting the frigid North from pathogens in the warmer South, notes Michael Grigg, a molecular parasitologist with the U.S. National Institutes of Health and an adjunct professor at University of British Columbia. But as the Arctic melts, parasites can move more easily across latitudes and survive much longer journeys. So: cat poop gets flushed down the toilet, parasite gets in the water, water circulates up north, and voila, belugas get a bad case of cat gut.

If the theory proves accurate, this won’t be the first time an organism has ended up somewhere unexpected thanks to climate change. In 2001 a deadly tropical yeast invaded Canada’s Vancouver Island when several lifeless porpoises washed ashore. Kitty litter disease is tame compared to what scientists found when they opened up the porpoise corpses: organs bloated by flower-shaped tumors and yeast infections eating their way through the animals’ skulls. Eight people also died from the grisly outbreak.

The culprit was a fungus that originates in Australian eucalyptus tree bark. Then, as now, scientists were surprised. How was a fungus from the tropics and subtropics surviving in cold Canada? But after running tests, it made more sense: the average temperature on Vancouver Island had increased by a degree or two Celsius during the past four decades. That doesn't sound like much, but it can make a huge difference in a microorganism’s survival.

Even though the Alaskan belugas aren’t exhibiting any signs of illness, the emergence of T. gondii in Arctic waters means the end of a traditional part of the Inuit diet: raw beluga meat. For the rest of us, it’s a reminder that climate change is turning our planet into a giant Petri dish with everything sloshing around inside—and we might not like the unexpected organisms we find ourselves curled up next to.

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image of Sarah Tory
Sarah Tory is pursuing an MFA in writing at Columbia University. She previously wrote for the news blog at Slate and has reported on the environment and energy for the Santiago Times in Chile. She is from Canada. MORE STORIES ➔
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Could part of the problem be that there are just too many pet cats? All of that cat litter has to go somewhere, over population of people has other effects also.