Do Wolves Kill More Often When Grizzlies Are Around To Steal Their Food? Research Says No.
Just like a lunchroom bully, brown bears (or grizzly bears, as Americans are more likely to refer to them) regularly steal food killed by other carnivores. As such, those carnivores usually have to kill more often to get enough food when brown bears are present. But research conducted in both Yellowstone and in Scandinavia suggests that this may not be the case for wolves.
“What we expected to find was that bears would increase wolf kill rate. And what we were kind of thinking was that well, you know, brown bears are really good at coming in and stealing wolf carcasses. So wolves make a kill, a brown bear comes in, and they’re generally able to dominate that carcass," explains Aimee Tallian, the study's lead author. "Lynx and mountain lion will abandon their kill quicker, and that will make them go make another kill sooner than they otherwise would have. So there was some thought that wolves did the same thing. But what we see was that there was actually a decrease in wolf kill rate where brown bears and wolves [overlap].”
New studies will need to be conducted to see why wolf kill rate decreases in the presence of brown bears. It is possible that wolves are sticking around longer after getting bumped by a brown bear, just to see if they will get another chance to feed. That waiting around could increase the time between wolf kills, and thus decrease wolf kill rate.
Nevertheless, the counterintuitiveness of these findings point to something that Tallian finds wonderful about the scientific process.
“In science we really aren’t trying to prove our own assumptions. We had this assumption of the way our ecosystem is working, and we did a study, and we found the exact opposite result. And so that’s one of the cool things about science and science exploration, is getting to know how the world works, even in the face of proving ourselves wrong.”
The study, Competition between apex predators? Brown bears decrease wolf kill rate on two continents was published in Proceedings of the Royal Society B on February 7.