Pros
In the 1970s, gray and red wolves were two of the first species to appear on the Endangered Species Act. Since then, their numbers have been on the rise, but gray and red wolves are still absent in the areas where they once flourished, including the Northeast, Pacific Northwest and southern Rockies. Wolves play a pivotal role in natural ecosystems, keeping the numbers of their prey in check. Interfering with nature and trying to eradicate species has long led to human/animal conflict. When predators' numbers are reduced, their natural prey overwhelms the ecosystem.
Cons
Wolves kill livestock, but not large amounts. The numbers of natural prey have dwindled in areas where humans have cleared land or put livestock. Sheep or cows are food for a wolf pack. Some livestock are easy targets due to size, age or illness, similar to in the wild. With their natural prey, wolves often pick off young, elderly or ill animals due to the easier target. Prey in these conditions normally don't move as fast, creating a quicker meal for the pack. Because of this, though, ranchers and farmers are fighting to keep wolves off the ESA due to a general ignorance and fear of wolves. Conservation societies are trying to work with livestock owners to implement ways to protect livestock from wolves such as separating sick or dead animals that may tempt wolves, and using fences to protect their animals.
Livestock Predation
A 2005 study ranked killings of cattle and sheep by wolves and other factors in states with wolf populations. In 2005, only 0.11 percent of cattle were killed by wolves. Domestic dogs killed five times more cattle than wolves, and coyotes killed 22 times more cattle than wolves. In these states, only 2-1/2 percent of sheep killings were caused by wolves. The top killer of cattle in 2005 was respiratory, health and calving problems.