Poisoned arrows in the Danish Early Mesolithic: Testing lithic ballistic morphometrics against faunal and archaeobotanical data

Throughout human deep history, lithic tool components became periodically very small. Such microlithic tools are the signature artefacts of the European Mesolithic in general, and the iconic Danish Mesolithic in particular. Sandwiched between the end of the Pleistocene and the emergence of agricultural lifeways, the Danish Mesolithic is characterised by marked changes in microlith design from lanceolates to geometrics and finally to transversal forms with wide front edges. These changes are synonymous with the transitions between the traditionally defined cultures of the Early, Middle and Late Mesolithic, yet the forces shaping them remain opaque. Here we present lithic, faunal, and a combination of archaeobotanical and palaeobotanical proxies, suggesting that the use of arrow poison was a likely driver for microlithic design change. An analysis of ballistically relevant morphometric attributes of lithics found in direct association with hunted prey suggests that the use of poison was prevalent during the Early Mesolithic when targeted game animals were also largest. Thereafter, lithic projectile points became larger and game animals smaller, likely reflecting Holocene faunal downsizing alongside changing hunting strategies. Palaeobotanical evidence from Denmark and southern Sweden suggests that a wide range of toxic plants were available throughout the Holocene. Cumulatively, these lines of evidence suggest that the use of arrow poison may have been widespread during the Early Mesolithic and declined thereafter despite readily available toxins.