MSU Professor Scott Creel has been known to stir a few pots, according to Department Head of Ecology David Roberts. Taking the stage, Creel joked that he was here to “stir the pot” again with his hour-long speech exploring the relationships among predators, prey and people. There are 245 species of carnivores in the world, and only 31 of these are larger than 30 pounds. Of those 31 species, almost all of them are very rare. Creel explained that when most people think about predators’ effect on prey, they only think directly: how many prey animals were killed by predators? In his research throughout Montana studying wolves, and in Africa studying African wild dogs, leopards, lions and hyenas, Creel focused on the other half of the equation: how does prey affect predator behavior, or what is the risk effect? Do those effects lead to a natural decline in prey?
The simple answer is: yes. In studying the reintroduction of wolves in Yellowstone, Creel and a group of graduate students compared the Environmental Impact Assessment (EIA) with their data. According to Creel, the EIA was “as thick as six New York phone books,” and not accurate in representing the impact of reintroduction. He and his team of graduates observed elk mating and feeding when wolves were not present, and how that changed when they were present. Turns out, when wolves are present, elk retreat to the woods — not their ideal habitat for food gathering. Female elk stay much more alert when wolves are around. The act of chewing or grinding their teeth wouldn’t allow them to hear very well, so they stand on guard, not eating. During the winter elk are already starving, but with wolves introduced the few nutrients they would normally be getting are cut in half. This leads to a high mortality rate in both unborn and fairly young calves. In order to realistically understand the effects of predators on prey, scientists cannot only consider predation but also risk effects.
The second half of Creel’s lecture discussed the effect of humans on prey. Some animal population decline is “a matter of law enforcement and economics,” while trophy hunting makes already fragile populations even more fragile. He pointed out that in Africa, village members poach mammals that lions would normally eat, or the lions themselves walk into traps and die. In game management areas where lions are allowed to be hunted, the leader of a pride is often targeted. When that lion dies, the next leader must kill off all the cubs so the female lions will be interested in mating again. Creel pointed out that there are things being done to prevent the illegal poaching of lions and lions’ prey within wildlife reserves, and suggested that more be done about trophy hunting, which is not sustainable. With only 31 species of large carnivores left, Creel argued that humans have an ethical responsibility to protect them to the best of their ability.