 This mandible (jaw) is estimated to be 1.5 million years old and it is characterized as having a robust build with large molars and reduced incisors.The specimen is believed to be an adult male.Peninj 1 was found in 1964 at a site in Tanzania called Peninj, west of Lake Natron and about 80 km (50 miles) from Olduvai Gorge, a major paleoanthropological site.