Last winter, researchers at the Minnesota Department of Natural Resources (DNR) discovered that moose in the far north state are dropping like giant, gangly-legged flies—declining at the speedy rate of 35 percent between 2012 and 2013. In addition to tangles with the state’s booming wolf population, studies showed that moose are also suffering from blood-draining ticks, brain-eating worms, climate change, and disease.
In response to the discovery, the DNR has closed its moose-hunting season for the first time in decades.
But researchers in another country halfway around the world are finding that the moose there are also suffering their own abuses. During the spring of 2007, scientists in Norway found that moose living in the northeastern corner began losing their coarse brown hair, leaving them looking like enormous, horned and naked mole rats (minus the buck teeth; plus the dulaps). Hunters, scientists, and tourists all puzzled over the sudden nudity. But later that year, a verterinarian named Madslien Knut discovered why the poor “swamp donkeys” were under attack. The culprit: a particularly nasty fly called the deer ked.
According to a story in On Earth magazine, deer keds drink blood. To get it, they crawl out of the ground and land on moose and deer. Once settled, they lose their wings, burrow into the flesh, and start sucking. While feasting, they meet often other deer keds doing the same; then mate and propagate. Unlike other bugs, deer keds produce only one larva at a time. But those singluar babes immediately begin burrowing into their host’s skin. Once the larva pupates, it “hops off the moose and holes up in the soil where someday it too will turn into a winged adult,” reports On Earth.
This is all tolerable when deer keds living on moose retain their “normal” numbers of 3,500. But in her study, Knut discovered Norwegian moose infested with 6,000 to 16,500 deer keds. “The researchers aren’t positive why more deer keds would correlate with pathological hair loss,” reports On Earth, “but they have some theories. Perhaps the excessive number of parasites feeding 15 to 20 times a day is simply too much for moose skin to handle, resulting in a widespread inflammatory reaction. Or maybe that many bug bites alters blood flow in some way that negatively impacts hair papillae. In any case, whatever was happening to the moose was more than a cosmetic problem.”
On Earth says that Knut never came to any conclusive answers, but determined that the parasite boom may have had something to do with unseasonably warm temperatures in Norway. The year preceding the great moose balding, Norway had its highest temperatures since record-keeping began in 1940. Researchers reportedly believed that an unseasonably warm summer and autumn preceding the breakout allowed more pupae to live to adulthood. Moose in Minnesota aren’t experiencing hair loss, but their rapid decline—a whopping 52 percent loss since 2010—has researchers at least as worried as Knut was.
According to the DNR’s website the die-off is puzzling for a number of reasons. So far, they’ve attributed it to everything from brain-tunneling parasites to higher average temperatures. Earlier this month, journalist Jessica Benko went out with DNR researchers on a moose-tracking mission, during which her team found a dying moose that they put out of her misery. One researcher said the job never got easier but that the current moose crisis demands such action.
The Minnesota DNR never returned TakePart’s calls for an interview. But Benko reports that researchers are finding disturbing reasons for the moose die-off. She writes that they discovered “a dizzying array of parasites and pathogens,” in moose brains, “including one that scientists have yet to identify.
“Four percent of the moose brains had healed-over tracks from brainworm,” Benko continued, “which can cause death if the worm burrows through critical tissues of the brain. Another ten percent had brain lesions of unidentifiable origins. Thirty percent had cysts in their livers from Fascioloides magna, giant liver flukes that can grow up to three inches long and migrate elsewhere in the body.” And more than 30 percent tested positive for either West Nile Virus or West Nile’s so-called “evil twin,” Eastern Equine Encephalitis.
To make matters worse, rising temperatures also seem to be affecting the moose. As Benko writes, “the Minnesota researchers have also found that rising temperatures correlate to higher mortality rates in both the state’s northwestern and northeastern moose.”
It remains to be seen if higher temperatures really are critically affecting moose survival. If yes, the Norwegian and American moose remind us that there is no end to the permutations in which the effects of climate change come to be felt, even within a single species.