Fur trappers will tell you that it is in their interest to catch only the species they are after, and that they have the skills to set traps that will only catch those species. The sad reality is that most traps are notoriously indiscriminate. Nooses designed to catch squirrels running along limbs may ensnare woodpeckers taking the same route, or a curious jay. Leghold traps or footsnares set for foxes may snap on the foot of a deer or a dog or anything else that steps on the trap. Baits meant for wolves are known to attract eagles, rare species such as wolverines, or other non-target animals. A companion dog out walking with her owner or a cat near a stream may suddenly be crushed by a Conibear trap set for muskrats. Even people, particularly curious children, can be caught or hurt by these traps.
Leg hold traps are cruel and inhumane. Animals that get caught in leg hold taps can suffer for days. Animals have been known to chew their leg off to try to get free from the trap. Oftentimes the victims suffer severe physical injury, psychological trauma, thirst, hypothermia, and predation.
Trappers have designed a class of "quick-kill" traps that supposedly kill instantly by slamming shut on an animal's body, crushing vital organs. Like all traps, they don't always work as planned, often with horrific results. The animal may enter a "quick-kill" trap the wrong way, and is partly crushed, and dies slowly. Snow and ice conditions can prevent proper closure. Aquatic mammals, like beavers, reflexively close off their air passages when submerged, and slowly suffocate while frantically trying to reach the surface, dying in terror without actually drowning.