What type of device is necessary on leg-hold traps to prevent excessive stress on trapped animals?

A tension device is essential on leg-hold traps to prevent excessive stress on trapped animals. This device plays a crucial role in regulating the amount of pressure applied to the animal's leg once it is captured. By incorporating a tension device, the trap can maintain a balance between securely holding the animal and minimizing pain and injury. This is particularly important in ensuring the ethical treatment of wildlife, aligning with best practice standards in trapping.

The function of the tension device helps to allow captured animals some movement, thereby reducing the risk of injury due to prolonged stress on their limbs. This addition reflects the trapping community's desire to promote humane practices in wildlife management and conservation.

In contrast, while other devices, such as release latches, guard plates, and different trap designs, can contribute to the overall effectiveness and safety of traps, they do not specifically address the critical issue of stress mitigation during the animal's capture. Release latches may help in the safe release of animals, guard plates can prevent accidental capture of non-target species, and half-moon designs can influence the trap's efficiency or effectiveness, but none of these directly serve to manage the degree of tension applied to a trapped animal's leg like a tension device does.