With cheetah population in southern Africa found to be 11 per cent smaller than recent estimates, an international team of scientists has called for uplisting the cats' conservation status from "vulnerable" to "endangered" on the International Union for Conservation of Nature (IUCN) Red List. Populations of cheetahs in southern Africa have declined as farming and other human activities push deeper into the free-roaming cats' range, said the study published in the journal PeerJ. Fewer than 3,600 adult cheetahs remain in the region, the researchers found. This new assessment is 11 per cent lower than the IUCN's most recent population estimate in 2015, adding urgency to calls from scientists to uplist the cheetahs' conservation status. To conduct the study, the researchers mapped and analysed more than two million collared cheetah observations made between 2010 and 2016 across 789,700 square kilometres of open grasslands in Namibia, Botswana, South Africa and Zimbabwe. "This is the area with the largest population of free-ranging cheetahs left on Earth. Knowing how many cheetahs there are and where they occur is crucial for developing suitable conservation management plans for the species," said Varsha Vijay, a doctoral student at Duke University in the US. Protecting cheetahs who live on, or travel through, privately owned livestock farms or game preserves is a particularly pressing conservation issue, said Florian Weise, programme coordinator at the nonprofit Claws Conservancy, who co-led the research with Vijay. "The future of the cheetah relies heavily on working with farmers who host these big cats on their lands and bear the heaviest cost of coexistence," Weise said. Interviews with farmers who share their land with cheetahs showed that nearly half of them consider cheetahs a problem, and about one in four actively kill or trap the cats to protect their herds. These losses can cause population declines, especially when reproductive conditions are not optimal, the researchers noted.