The Anthropocene fossil record of terrestrial mammals

Abstract

• The number of humans and their animals greatly exceed that of wild animals. • Humans, pigs, cattle, and sheep will dominate input to any future fossil record. • Human activities markedly change the nature of mammal remains and burial sites. • The modern mammalian fossil record will thus be unique in Earth history. This paper reviews how human impacts produced a marked shift from natural processes in the potential input of terrestrial mammals to the fossil record, both in composition of the mammal taxa and in processes controlling their preservation. These issues are key considerations in predicting the future fossil record of the modern vertebrate fauna and determining if there will be a resultant “Anthropocene” biostratigraphic unit. We show that a cosmopolitan fauna of humans and their domestic animals will dominate the potential fossil record. The chance of a wild animal becoming part of the fossil record has become very small. Instead, the future mammal record will be mostly cows, pigs, sheep, goats, dogs, cats, etc., and people themselves. The review also shows major unique anthropogenic impacts on the preservation potential of mammals. These impacts include alterations in the distribution and properties of natural sites of preservation, associated with shifts in land use and climate change; the production of novel sites for preservation, such as landfills and cemeteries; and changes in the biostratinomy of animal and human carcasses. Hunting and butchering produce distinctive bone fragments and assemblages. Use of large agricultural equipment and increased domestic animal density due to intensive animal farming likely increases the rate of and changes the kind of damage to bones. In sum, the mammalian fossil record of the modern era should be unique in Earth history and may help distinguish the boundary of the proposed Anthropocene time period.