Siskiyou-cascade
Guides
Bombus franklini
Franklin's bumble bee, Franklin's bumblebee
Bombus franklini is a critically endangered bumble bee species with the most restricted range of any bumble bee in the world, confined to a 13,300-square-mile area spanning five counties in southern Oregon and northern California. The species has not been observed since 2006, despite intensive monitoring by entomologist Robbin Thorp from 1998 until his death in 2019. Listed as endangered under the U.S. Endangered Species Act in 2021, it is feared extinct due to severe population decline from an estimated 94 individuals in 1998 to zero confirmed sightings since 2006. Genomic research indicates long-term population decline driven by bottlenecks and environmental stressors rather than pathogens alone.