Researchers find 300,000-year-old hearth in Israel They weren't cooking brontosaurus burgers -- but maybe mammoth meat? A team of researchers has uncovered the oldest hearth in Israel, a 300,000-year-old fire pit where prehistoric humans roasted ancient meats. Scientists estimate that humans discovered fire over a million years ago, and this find helps determine when our ancestors learned to cultivate it and use it as a tool, said Ruth Shahack-Gross of the Kimmel Center for Archeological Science at the Weizmann Institute of Science. "These findings help us to fix an important turning point in the development of human culture - that in which humans first began to regularly use fire both for cooking meat and as a focal point - a sort of campfire - for social gatherings," Shahack-Gross said in a press release. They also tell us something about the impressive levels of social and cognitive development of humans living some 300,000 years ago. The hearth was discovered in the Qesem Cave near the central Israel town of Rosh Ha'ayin, a spot archaeologists have plumbed for nearly 15 years. During recent work there, Shahack-Gross spied a thick deposit of wood ash, hardened and compressed over the centuries into sediment and buried in the center of the cave. By taking thin slices of it and studying it under a microscope -- using a technique called infrared spectroscopy -- she and her colleagues Avi Gopher and Ran Barkai of Tel Aviv University determined that bits of bone and soil that had been heated to very high temperatures were mixed in with the ash. There were also tiny but clear layers in the ash, which she called conclusive proof that the area had been the site of a large hearth that was used over and over again. Around the hearth area they found flint tools that were clearly used for cutting meat -- early knives and forks, in a sense. Flint tools found just a few feet away had a different shape and were clearly designed for other activities. Also in and around the area were burnt animal bones -- further evidence for use of the fire pit for cooking meat.