Officials at Grand Canyon National Park say a bobcat was recently found dead in the South Rim Village with high levels of rodent poison in its system.
While the so-called "rodenticides" are prohibited in the park, coyotes, fox, mule deer, chipmunks and other animals have died after being exposed to the chemicals.
According to Grand Canyon biologists, the poisons can linger in the food chain for weeks and kill animals that eat other animals that’ve died from the chemicals.
They also point out that endangered California condors, which are scavengers, are particularly susceptible to rodent poisons.
Officials urge employees and residents of Grand Canyon to instead use available free rodent kits and arrange for the pickup of rodenticides by the park.