Long ago, there used to be other types of hominins on Earth. They were like modern humans, but not the same. "Homo sapiens" are the only type of hominins who are alive today. The earliest known fossils of genus "Homo" have been called "Homo habilis" (handy man). The first fossils of "Homo habilis" were found in Tanzania. "Homo hablilis" is thought to have lived about 2.2 to 1.7 million years ago. Another human species thought to be an ancestor of the modern human is "Homo erectus". There are other extinct species of "Homo" known today. Many of them were likely our 'cousins', as they developed differently than our ancestors. A theory called the Sahara pump theory has been used to tell how different species of plants and animals moved from Africa to the Middle East, and then elsewhere. Early humans may have moved from Africa to other parts of the world in the same way.