The invasion of just two species has cost $17 billion over the past 35 years, according to a new study examining the effects of alien reptiles and amphibians. Brown treesnakes (Boiga irregularis) and American bullfrogs (Lithobates catesbeianus) accounted for the lion’s share of the cost of invasive reptiles and amphibians, costing $10.3 billion and $6 billion from 1986 to 2020, respectively. Brown treesnakes have wiped out populations of small animals in Guam and have caused problems to human infrastructure and health. Bullfrogs have elbowed out other smaller species in the western U.S. as they spread from their native range in the East. A remaining 19 reported invasive species of reptiles and amphibians only accounted for less than $1 billion in the same time period.