Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: FRIDAY, March 16, 1990 TAG: 9003192664
SECTION: CURRENT PAGE: NRV1 EDITION: NEW RIVER VALLEY
SOURCE: CATHRYN McCUE NEW RIVER VALLEY BUREAU
DATELINE: BLACKSBURG LENGTH: Medium
Somewhere on university property, right here in town, three black bears are hibernating. One bear is nursing three cubs, each weighing less than a pound.
Vaughan has good reasons to want the bears' location kept quiet: safety for humans, safety for the bears, and safety for his research project - the only one of its kind that he knows of.
His six-year study of the link between nutrition and reproduction rates could help wildlife experts manage American black bears in Virginia and other states.
"That work down there will not only be of benefit to us but to everyone in the country," said bear specialist Dennis Martin of the Staunton office of the state Department of Game and Inland Fisheries.
After four years of studying bears in captivity in Blacksburg, Vaughan has determined that the availability of food makes all the difference in whether pregnant bears have their cubs.
His findings so far indicate that if females can't get enough to eat during the fall, they will spontaneously abort their fertilized eggs during hibernation.
Bears breed in the summer. During the fall, they go through a hyperphagic stage, "which means they eat a lot," Vaughan said.
They don't eat or drink during the winter months, but live off their body fat. Pregnant females must be fat enough to survive winter as well as feed their cubs, which are born around late January and early February.
"It would have to do with how much fat I have on my body and can I go into the den and have enough milk to nurse," the bear expert said, speaking as one of his furry research subjects.
"These bears don't ask these questions, but from a physiological standpoint, that could happen."
That's apparently what did happen with two of his bears this year.
Both were pregnant when Vaughan got them in August. The third female came in December, too late to be part of the study.
One bear, No. 14, was kept on a maintenance diet of Omnivore Chow and gained only six pounds from her original 145 pounds.
"The other one, she just porked out," Vaughan said. Bear No. 15 was fed lots of chow and nearly doubled her weight - from 120 pounds to 206 pounds.
She alone had cubs. A sonogram on the other bear shows remnants of a placenta - signs she had been pregnant but had spontaneously aborted.
"It'd be nice to know what's the breaking point - how much fat they'd have to put on to bear young," Vaughan said.
He plans to bring bears to Tech to hibernate for two more winters to gather more data before making formal conclusions.
The information could eventually be used by wildlife managers at the Department of Game and Inland Fisheries and other agencies to issue hunting licenses, for example.
"You don't want to harvest them if they've had a poor year in reproduction," Vaughan said.
The best estimate of black bear population in Virginia is between 2,500 and 3,000.
"That's ballpark," bear specialist Martin said. "They just can't hold still for us to count them." The population in recent years seems to have been stable and even to have increased in some areas, he said.
The majority of black bears live in and around the Shenandoah National Park, which is where most of Vaughan's bears hail from.
He has a deal worked out with the wardens, who each year give him up to six "nuisance bears" captured in apple orchards, cornfields or near population centers.
Wildlife managers have been relocating nuisance bears for two years to southwestern Virginia to bolster the dwindling population. Bears No. 14 and 15, along with the other adult bear and the cubs, will be set free this spring in this part of the state.
"I'm sure they're going to know they're in a different place," Vaughan said. "Bears are notorious for homing."
But the bears should fare no worse for having spent the winter at the university. Vaughan said he and his associates try to avoid taming the bears in any manner.
He tranquilizes them, weighs them, takes blood samples and measures fat levels every 10 days. The whole process takes about a half-hour. One of his students makes a quick check on them daily, and that's it.
"It might even make them more averse to humans," Vaughan said. "They've been around them so long they might just want to stay hidden."
His other bears have all gone back to the wild without problem, he said. Vaughan wants to put transmitters on No. 14 and No. 15 for a year to see how they do and where they go after being released in mid-May.
"After hunting season," Vaughan noted.
by CNB