Bear Naked Truth

Goings-on with black bears in the Tahoe Basin and beyond

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  • August 31, 2021
A black bear lies on the ground next to a tree in the Tahoe Basin after release into the wild.

Earlier this year, the young female black bear revels in her newfound freedom upon release into the wild following months of care and rehabilitation in captivity after being struck by a vehicle in the Lake Tahoe Basin. CDFW photo.

While they can thrill tourists and residents alike with their mere presence, antics and brazen behavior, life is no vacation for the Tahoe Basin’s black bears. They often face many more serious threats to their survival and well-being – traffic, disease, a garbage-filled diet, human conflicts and now wildfire – than many of their wildland counterparts.

That point was driven home recently when veterinarians at the California Department of Fish and Wildlife (CDFW) had to euthanize a year-and-a-half old female bear – one of the “South Shore Four” – released this spring back into the wild after seven months of rehabilitation at Lake Tahoe Wildlife Care (LTWC). The bear arrived at LTWC in September 2020 as a 50-lb. cub suffering a broken leg after being hit by a car on Emerald Bay Road near Eloise Avenue.

Rehabbed alongside three local orphaned bear cubs – two males and one female – the young females were released together last April about 70 miles from South Lake Tahoe.

The one female with the healed hind leg was of particular concern to biologists. The cub’s mother was a known problem bear – raiding garbage cans, breaking into garages and cars – and was thought to be teaching these same behaviors to the cub before the cub was struck by a car and taken to LTWC for rehabilitation.

Outfitted with a GPS tracking collar and a No. 83 blue plastic tag in her left ear, the female bear, weighing some 150-lbs. at that point, headed almost immediately back to South Lake Tahoe, the bear’s collar sending signals from the Freel Peak area. Campers later spotted the bear in the Zephyr Cove area and South Lake Tahoe residents reported seeing the bear in the exact backyard where it was believed to have been born. The bear showed little fear of either cars or people.

Then, on May 24, the bear was found unresponsive, sprawled out on its side at the base of a tree in a residential backyard along Freel Peak Ave., leading to initial speculation that the bear had been struck once again by a vehicle. An emergency visit to a local animal hospital, however, showed no sign of trauma. The bear was returned to LTWC for care and observation.

Although the bear improved after a week, LTWC staff agreed that the bear never recovered fully. Mentally, it seemed like a different bear altogether than the one staff had cared for prior to its April release – mentally dull and lethargic.

In June, the bear was moved yet again – this time to CDFW’s Wildlife Health Lab near Sacramento for further observation and examination by CDFW veterinarians.

Given the mental dullness and its lack of fear around people, biologists and veterinarians suspected encephalitis – or inflammation of the brain – as the root cause of the bear’s problems. The neurological disorder has turned up increasingly in the Lake Tahoe Basin’s black bear population. A cause for this disorder has yet to be identified and currently there are no treatments.

At CDFW’s facilities, the female bear remained unsteady on its feet with an abnormal gait and mental dullness. Showing no signs of physical or mental improvement, the decision was made to euthanize her due to the grave prognosis for a return to normal function and release back to the wild.

A post-mortem examination to determine a cause of the physical and mental abnormalities was inconclusive. The examination showed no evidence of encephalitis or recent physical trauma but did find “degenerative changes in the brainstem.” Additionally, trace amounts of bromethalin were detected, revealing exposure to this neurotoxic rodenticide.

Still, relatively little is known about the potential effects of bromethalin in wildlife, and veterinarians were unable to determine whether it could have caused the degenerative changes in the brain or the physical and mental changes observed when the bear was alive.

CDFW biologists continue to monitor the three remaining “South Shore Four” bears in the wild. These bears are now confronting the latest threats to their survival and well-being – namely, the Caldor and Tamarack fires.

Categories: Disease, Neurological Disorders, Rehabilitation, Wildfire
  • May 14, 2021
A tranquilized male bear lies on a gurney, blindfolded, as its vital signs are monitored at Lake Tahoe Wildlife Care.

A young male bear, one of the "South Shore Four" rehabbing at Lake Tahoe Wildlife Care the past year after being orphaned as a cub, is sedated while being outfitted with identifying ear tags and a GPS tracking collar prior to release back into the wild in April. CDFW photo by Shelly Blair.

The California Department of Fish and Wildlife (CDFW) licenses and partners with nearly 100 private wildlife rehabilitation facilities around the state that provide important care, shelter and veterinary services to injured, orphaned and other displaced wildlife of all kinds.

What happens to these animals upon their recovery and release back into the wild often remains a mystery. That’s true even at the only two rehabilitation facilities licensed in California to work with black bears: The San Diego Humane Society’s Ramona Campus in Southern California and Lake Tahoe Wildlife Care in South Lake Tahoe.

While the rehabilitated bears are almost always outfitted with an identifying ear tag or two prior to release, a feel-good video of the bears fleeing a portable trap on their way to freedom is often the last time biologists and wildlife rehabbers ever see them.

With a second chance at life in the wild, do the bears revel in their newfound freedom and stay as far away from people as possible and successfully transition to natural food sources? Or, after months of being cared for and closely watched at a rehabilitation facility, are the bears more comfortable around people, seeking out the nearest rural communities for the easy access to human food and garbage they can often supply? Do bears kept together in a rehabilitation facility and released together stay together in the wild? If so, for how long?

These are among the questions CDFW wildlife biologists are seeking answers to with the recent release of the “South Shore Four” – four young black bears, two males and two females, rehabbing together the past year at Lake Tahoe Wildlife Care where they arrived as young-of-the-year cubs. Three of the four were orphaned when their two mothers were hit and killed by cars – one of the female cubs suffering a broken leg from a vehicle strike.

Fully recovered, weighing between 150 and 190 pounds each and old enough to survive on their own, the “South Shore Four” were released into a nearby national forest last month, two bears at a time. Three of the four cubs were fitted with GPS tracking collars that will alert biologists to their whereabouts four times a day if canopy cover allows. Biologists also receive a mortality signal 12 hours after no movement so that recovery and cause of death can be determined.

“We’re hoping to understand their movements directly after release, whether or not the ones that were released together stay together, the distances they travel and where they’re going,” said Shelly Blair, CDFW’s wildlife biologist for Alpine and El Dorado counties. “This is essential information to monitor the after-effects of almost a year in captivity and where they go. If they’re moving toward trouble – a campground or a community – we’ll be able to see that and get ahead of it if possible.”

GPS-tracking collars are an important research tool for wildlife biologists but also something of a precious commodity that cost between $800 and $2,000 each.

The collars are fastened around the bears’ necks with surgical tubing that will expand as they grow. After a few months of exposure to the elements, the tubing will deteriorate, and the collars will fall off to be recovered later. At that point, the South Shore Four’s research contributions will be short and likely complete, but will yield valuable information about the bear rehabilitation program and help improve CDFW's efforts to ensure the best possible outcome for these animals to be successful wild bears.

Video: Watch as two of the 'South Shore Four' are returned to the wild.

Categories: Public Safety, Rehabilitation, Research

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