Research note: A 50-year increase in vehicle mortality of North American mammals

Abstract

Mortality of mammals from vehicle collisions is common, but there remain questions regarding how species traits influence vehicle collision vulnerability. We analyzed a database of North American mammal cause-specific mortality to examine factors influencing vehicle mortality. Our dataset consisted of 421 studies that monitored 34,798 individuals across 66 species including 740 vehicle mortalities. Vehicle mortality increased 4-fold over the study period (1965–2017), from 3% to 12% of total mortality between the first and last decade. Omnivores were more likely to die from vehicle mortality than herbivores. Vehicle mortality was highest for species at intermediate body masses (6–12 kg). Sociality, foraging behavior, diel behavior, and scavenging behavior did not influence vehicle mortality. The habitat and dietary flexibility of omnivores may put them at increased risk of vehicle collisions. The increase in vehicle collisions over the past 50 years reiterates the need for mitigation measures to conserve North American mammal populations.