Muddy footprints suggest 2 species of early humans were neighbors in Kenya 1.5 million years ago The Associated PressFootprints reveal the coexistence of two human species 1.5 million years ago EL PAÍS USARare footprints suggest two of our prehistoric ancestors may have met The Washington PostFootprints Suggest Different Human Relatives Lived Alongside One Another The New York TimesFossil Footprints Show Two Ancient Human Ancestors "Crossed Paths" NDTV