The hole for the trap set should be dug about 15 to 20 inches from
a carcass, a single undisturbed scratch hill, or a tree on which a
scent station has been placed, or directly in a trail where it narrows
naturally or is made to narrow by rocks, brush, or other obstructions
placed at the sides. (Fig. 3.) The hole should be only slightly larger
than the trap, and just deep enough to hold the set at a level slightly
lower than the surrounding ground, with the drag and chain buried beneath
it. The drag, which should preferably be of ½-inch wrought iron, should
be attached to one end of the chain by a figure-8 swivel and it should
end in two well-curved prongs. (Fig. 1.) Bedding the drag under the
trap, of course, requires more excavation. The drag chain should be at
least 8 feet long and attached to the base of the trap or to one of the
springs. At scratch hills it is well to place a trap on either side, the
springs at right angles to the known direction of approach. In a trail
the traps should be in line, the springs at right angles to the direction
of travel. Experiments have proved that most of the larger predators,
and particularly the mountain-lion, tend to avoid stepping directly on
any hard object in a path. Knowing this tendency, the trapper may place
a stick or a stone between the two traps and another at each approach;
these will cause the animal to break its gait and step into one of the
traps rather than over or between them. In approaching a scratch hill,
a scent station, or a carcass where sets have been made, or in passing
over a blind set in the trail, the predator is usually caught by one of
the forefeet, though it may step into a bedded trap with a hind foot. No
scent is used at carcass or blind sets. (Pp. 4, 6.)