However, their primary purpose was not for burial of the dead but for use by the living. (ambergrisCaye.com)
Oil and gas result mostly from the rapid burial of dead microorganisms in environments where oxygen is so scarce that they do not decompose. (scientificamerican.com)
The most recently discovered human species, Homo naledi, had a brain about the size of an orange, but it nevertheless possessed enough of a mind to perform ritual burials of its dead. (scientificamerican.com)