Common law, as applied in the East, presupposed that cattle would be fenced, making cattle owners responsible for any damages their animals caused. Only the Fund for Wildlife has tried to construct a fence along part of the migration route to keep the bison in the park, and for a time the Fund paid the owners of a ranch that borders the park to close their property to hunting. The cattlemen on the plains also used “human fences,” or line camps, to enforce their rights to cattle and land. As with land, new institutions were also needed in the West for defining and enforcing property rights in livestock. Identifying animals by their natural markings was also feasible on farms that had only a few head of livestock. Especially in the arid states on the western plains, where water was essential for raising crops or livestock, land with available water became increasingly scarce and the value of water rights rose.