South Africa is home to thousands of rhinos, including critically endangered black rhinos (Diceros bicornis) and near-threatened white rhinos (Ceratotherium simum). Poachers kill hundreds of rhinos every year, usually for the animals' horns (SN: 4/9/20). The country's police force adopted forensic entomology into its poaching prevention arsenal in 2014, training officers to collect insect evidence found at wildlife crime scenes. The process works the same with rhinos as it does with humans, says Dadour, now of Source Certain, an Australian company that verifies the origin of agriculture and seafood. Officers collect adults, larvae and eggs of carrion insects such as flies and beetles from the victim. Carrion insects are quick to find and lay eggs on a dead body - often descending in under an hour - which then hatch and develop at a predictable pace. In that way, they act as a biological clock. Forensic entomologists can estimate how long a body has been dead based on what insects are present and the life cycle stage of the insects’ offspring. That estimate is called a minimum postmortem interval. The method is most accurate before and during active decay; as decomposition progresses, accuracy drops. "When the conditions are right, it can be very useful," says Martin Villet, a forensic entomologist based in Cape Town, South Africa. Investigators can use the data to track down killers and prosecutors can use it as evidence in the courtroom.