Bear affliction spreads

By Mike Lynch

Adirondack guide Joan Collins was driving on the state highway through Newcomb a couple of years ago when she noticed a black bear crossing the road. “It had patches of hair that were just hanging (off of it),” she recalled.

A naturalist, Collins said the bear appeared to have mange, a skin disease that is caused by microscopic mites that dig into the skin and lay eggs—and that appears to be on the rise in the Northeast.

Collins said she’s seen a few cases of mange in recent years after never seeing it before on bears. She said some of the animals have visited her property in Long Lake, and she finds the condition troubling.

“Mange is an absolutely horrible condition,” she said. “It (causes) a slow death. Their hair falls out … . They basically starve to death. It’s awful to see. They just become skin and bones.”

Bears and other mammals that have mange lose their hair because the mites cause the animals to itch the infected area. As a result, bears will scratch themselves to the point that they cause themselves to lose hair.

In some cases, bears will starve to death because they are spending all their time scratching the mites instead of searching for food.

The disease hits bears especially hard in the winter when they are hibernating. In some cases, the mites will wake the animals. The bears sometimes then leave their dens in search of food, unable to find any natural sources because there is no vegetation. In these cases, they can die of starvation or become hypothermic. Bears with 90 percent hair loss have been documented in the Adirondacks.

Complications also arise from the loss of hair and cuts caused by the intense scratching. With severe cases, bears get infections in their wounds.

Bears have a better chance of surviving mange in the summer, when it’s warmer and more natural food is available.

State Department of Environmental Conservation wildlife biologist Steve Heerkens has encountered bears that have lost most of their hair and have no fat or muscle. “I have seen bears that have died from mange, that if you looked at it quick, it doesn’t look like a bear at all.”

In recent years, the number of black bears with mange appears to be on the rise in several Northeastern states, including New York and Pennsylvania, according to the DEC. As a result, wildlife biologists throughout the Northeast are monitoring the situation more closely, and searching for potential treatment options.

Krysten L. Schuler, a wildlife disease ecologist with Cornell University’s Animal Health Diagnostic Center, has been working with state officials in Pennsylvania and New York to document and study mange cases in black bears. Schuler gets reports about mange from the DEC and the public, including trail camera images.

Schuler said there are three bear populations in New York State where individuals have mange: Adirondacks, Catskills, and western New York. The bears in the western part of the state appear to have gotten mange from bears in Pennsylvania. The Adirondack and Catskill populations seem to have gotten it locally, perhaps from other mammals.

Heerkens said bears are likely getting the mites from red foxes and coyotes and other bears because they share the same natural and developed habitats. “They are visiting the same dumpsters,” he said. “They are visiting the same campgrounds.”

Schuler said the disease was originally introduced to wild populations from domestic animals more than a century ago. Now more than 100 species of animals have it worldwide. In the Adirondacks, it first started becoming more common 10 to 12 years ago, said DEC spokesman Dave Winchell.

Winchell said mange cases don’t appear to be having a major impact on the bear population, which is estimated to be 3,500 to 5,000 in the Adirondacks. “Mange is not always fatal and has not caused any major population declines,” he said in an email. “However, as symptoms worsen, bears tend to be more conspicuous.”

Winchell noted infected bears may become more active during daylight hours, and seek food from garbages, bird feeders, livestock (mostly chickens), and livestock grain.

Heerkens works on the western side of the Adirondacks, inside and outside of the park. He said he first encountered mange in the early 2000s in the town of Western, just outside the southwestern corner of the park. He didn’t see it again until 2010, when he encountered it in the town of Salisbury, on the southwestern edge of the park. But since 2010, he said it’s really been on his radar. In recent years, he’s seen cases in Herkimer, Hamilton and St. Lawrence counties. “It’s not huge numbers but … everybody deals with a couple of mange cases every year,” Heerkens said. “Some years it seems to be worse than others.”

Wendy Hall, a wildlife rehabilitator at Adirondack Wildlife Refuge in Wilmington, said she has rehabbed about eight bears for mange in recent years. She is currently working with four cubs that have the condition. Over the years, the bears have come from Hamilton, Essex and Warren counties. Hall said the animals are put in isolation and given an anti-parasitic medication for the mites. If they have infections, they are given antibiotics.

In general, scientists say that it’s really hard to estimate exactly how many bears in the Adirondacks have mange because the animals live in the wild and may never come in contact with humans, especially those that live in remote areas.

DEC isn’t exploring treatment options for the animals in the wild, Heerkens said, and the strategy for the near future is just to document the cases.

“I suppose if the number infected animals jumped five-fold or started to really jump from year to year to year, there would be questions to ask,” he said, “but at this point I’m not aware of any effective treatment on a landscape level that you can do for these things.”