The reintroduction of wolves into Yellowstone National Park has an unexpected upside: It's helping to fatten up the bears, new research suggests. 
 
 The wolves have kept the park's population of elks (prey for wolves) in check, which in turn limits how many berry-producing shrubs the elks consume. As a result, the bears have more tasty berries to eat, finds a study published on July 29 in the Journal of Animal Ecology. 
 
 The study points "to the need for an ecologically effective number of wolves," said co-author Robert Beschta, a researcher at Oregon State University, in a statement. "As we learn more about the cascading effects they have on ecosystems, the issue may be more than having just enough individual wolves so they can survive as a species. In some situations, we may wish to consider the numbers necessary to help control overbrowsing, allow tree and shrub recovery, and restore ecosystem health." 
 
 Wolves were first removed from Yellowstone National Park in the 1920s, after which the elk population soared. The huge herds of elk heavily browsed aspen and willow in the park and reduced the berry-producing shrubs. Past studies showed the reintroduction of wolves in 1995 has led to willow and aspen populations rebounding. [Photos: The Wonders of Yellowstone National Park] 
 
 The reintroduction seemed to have a beneficial effect on bears. 
 
 Now, Beschta and colleagues have found the amount of fruit in grizzly bear scat doubled in August in recent years, which means the bears were eating more of it. The grizzlies love to graze on the park's many wild berry species, such as serviceberry, chokecherry, buffaloberry, twinberry and huckleberry. 
 
 "Wild fruit is typically an important part of grizzly bear diet, especially in late summer when they are trying to gain weight as rapidly as possible before winter hibernation," said study co-author William Ripple, a forest ecosystems researcher at Oregon State University, in a statement. "Berries are one part of a diverse food source that aids bear survival and reproduction, and at certain times of the year can be more than half their diet in many places in North America." 
 
 Because bears have made up for the decline in berries by eating more elk in the last 50 years, the berry bounty may also help offset the decline in elk. 
 
 Follow Tia Ghose on Twitterand Google+. Follow LiveScience @livescience, Facebook & Google+. Original article on LiveScience.com. 
 
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 This story was originally written for LiveScience and was republished with permission here. Copyright 2013 LiveScience , a TechMediaNetwork company. 
 
 How Yellowstone wolves are helping grizzly bears fatten up 
 
 The reintroduction of wolves into Yellowstone National Park has an unexpected upside: It's helping to fatten up the bears. 

 A wolf walks with a set of elk legs in the Hayden Valley after killing and eating it in Yellowstone National Park, Wyoming, in this June 20, 2011 file photo. 
 
 SALMON, Idaho | 
 
 SALMON, Idaho (Reuters) - The return of wolves to Yellowstone National Park may be helping imperiled grizzly bears to survive by keeping elk herds on the move and preventing them from destroying berries that are a staple food for grizzlies, according to a new study. 
 
 In the mid-1990s, the U.S. government released fewer than 100 wolves into the park and the wilderness near Salmon, Idaho, to restore an iconic Western animal that had been hunted, trapped and poisoned to near extinction in the Northern Rocky Mountains. 
 
 Today, roughly 1,700 wolves roam the Yellowstone border states of Idaho, Montana and Wyoming, where hundreds of the predators have been hunted and killed since being removed in 2011 and 2012 from the federal threatened species list. 
 
 Scientists suspected nearly two decades ago but couldn't say with precision that the reintroduction of an apex predator missing from the larger Yellowstone landscape for 70 years would help restore an ecosystem hobbled by overgrazing by elk, bison and cattle. 
 
 Research published on Monday in the Journal of Animal Ecology suggests Yellowstone wolves may play a pivotal role if threatened grizzlies are to flourish. 
 
 Yellowstone grizzlies showed greater quantities of berries in their scat after the wolves' reintroduction, which has thinned and dispersed elk herds and reduced concentrated foraging that can destroy berry bushes, researchers found. 
 
 "What is interesting and surprising here is that we have one large predator affecting another large predator," said Oregon State University ecologist William Ripple, the study's lead author. 
 
 OUTCRY OVER HUNTING 
 
 The report is one of the first to examine the relationship between the roughly 600 grizzlies in the Yellowstone area and the fewer than 100 wolves that frequent the park. There was a public outcry earlier this year after hunters killed a dozen of those wolves. Hunting is illegal in the park but popular in adjacent states. 
 
 Ranchers and hunters want to cut the number of wolves and grizzlies, complaining they prey on livestock and elk. Hunting groups like Rocky Mountain Elk Foundation blame wolf reintroduction for reducing elk numbers in Yellowstone's northern herd area by 80 percent, from an estimated 19,000 to less than 4,000, largely through predation. 
 
 Chris Wilmers, environmental science professor at the University of California-Santa Cruz who was not involved in the study, said the new findings add to a growing body of work showing how predators impact Yellowstone. 
 
 "You never have an eye on the whole ecosystem and how everything is connected until you see it working," Wilmers said. 
 
 Research suggesting wolves indirectly benefit bears comes as federal grizzly managers examine if climate changes will curtail production of whitebark pine nuts, a food crucial for bears trying to bulk up before hibernation. 
 
 That question is at the center of a lawsuit brought by conservationists against the U.S. government in 2007 when it sought to lift federal protections from a Yellowstone area grizzly population that U.S. bear managers said have made a healthy comeback from the brink of extinction. 
 
 A federal appeals court in 2011 upheld a lower court ruling that left protections in place for Yellowstone grizzlies because the government had discounted the impact of climate changes. An assessment of climate factors is expected in coming months, along with a possible renewed push to remove bears as protected and open the way for hunting. 
 
 (Editing by Cynthia Johnston and Grant McCool)
– Bears in Yellowstone are eating twice as many berries as they used to, and the reason is all about the intricacies of a wildlife ecosystem: The park brought back wolves, and they've been eating the elk that used to eat the berries, reports the Mother Nature Network. As a result, there are more berries for the bears, which like to gorge on them before hibernation. (Researchers figured this out the hard way—by examining bear scat.) On the face of it, this seems like pretty good news for the bears, and most of the coverage, like this story in Reuters, emphasizes how wolves are unintentionally helping the park's grizzlies. But here's another example of those ecosystem intricacies: The population of northern elk in the park has dropped from roughly 20,000 to 4,000 since the wolves' return in the mid-1990s, reports the BBC. And while the bears like to eat berries before hibernation, they like to eat elk calves when they wake up. Those calves are now harder to find, which means the wolves' appetite for elk may end up hurting bears in the long run, suggests a Yale expert. "Unfortunately, as wildlife ecologists (work) in a vast landscape such as the greater Yellowstone ecosystem, it is very difficult to unravel the complexity of the patterns." (More interesting wolf news: We can now identify individual wolves by their howls, and some even have "accents.")