Researchers Rachel Stone and Emmy Engasser spent a year baiting dung beetles in traps with dead rats on the Kansas prairie, as shown here, to evaluate whether dung exposed by decomposition or the carrion itself attracted the beetles. They found that more beetles congregated at the fore rather than the aft end of the carrion, which suggests they were drawn to the carcass itself, not dung in the gastrointestinal tract at its rear, as has been hypothesized in the past. (Photo by Emmy Engasser)