By Jeff Brown, PAWS Wildlife Naturalist
It's winter here at the PAWS Wildlife Center and the halls are much quieter this time of year.
The four yearling Black Bear patients are hibernating so they aren’t making a sound.
Staff and volunteers also must work quietly as to not disturb them. The bears are housed in enclosures that are kept dark to help mimic their natural dens. The main difference for these patients is that they aren’t denned up with their mom. Care in this state is quite simple as bears do not urinate or defecate while in their dens. This adaptation keeps bears safe from wild predators and allows them to recycle nutrients and conserve water.
Above: One of the signs reminding staff and volunteers to be mindful of the sleeping bears.
The term hibernation for bears has often been debated because their “sleep mode” state differs from other true hibernating species. A bear’s body temperature doesn’t decrease to the ambient temperature like a ground squirrel or a bat, and is only about 10 to 12 degrees lower than their normal body temperature. This means that they can arouse from this state relatively quickly. However, bears do reduce their metabolic rate so their breathing and heart rate are much slower. The debate regarding the proper term may continue but bears’ adaptations to winter are no less amazing. Check out this NPR story to learn more about their body’s response to prolonged rest.
Above: The cubs at PAWS before they went into hibernation.
Our patients are not the only bears hibernating of course. Bears all over the Pacific Northwest are denned up right now. For all of us that live in the wildland-urban interface (areas near or surrounded by unoccupied land), we must not relax our bear safety precautions. Bears, especially in the lowlands of western Washington, can come out of hibernation during warm spells in winter. In fact, bears won’t hibernate at all in some areas along the coast. It all depends on food availability. If bears do emerge from hibernation, they might be looking for quick calories in your garbage. Wildlife managers recommend that we maintain bear-safe garbage cans, clean barbeques, and continue other bear safe practices all year round.
Above: An example of a bear-safe garbage can.
The bears at PAWS will likely come out of hibernation earlier than most bears in the wild. They will start to stir in the next two months and we will return to normal bear care routines. Wild bears usually emerge in April but that can depend on elevation, snowmelt, and many other factors. As we look forward to spring, it’s important to start planning now to prevent conflict with bears. Washington Department of Fish and Wildlife’s website has great info about living with bears including this video, Western Wildlife Outreach provides services to King County and has a great cheat sheet for reducing bear conflict.
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