A spatial and temporal assessment of human-snake encounters in urban and peri-urban areas of Windhoek, Namibia

Wildlife is known to be attracted to cities as a result of the ecosystem services associated with synanthorpization. This however often results in conflicts between human activities and wildlife. Accidental encounters between snakes and people in urban areas is a problem Windhoek shares with many cities around the world. Globally, this conflict leads to numerous human envenomations, a serious and neglected health concern according to the World Health Organisation. It is estimated that between 4000 and 30,000 people die from snakebite envenomation annually in sub-Saharan Africa alone. Surrounded by farm and natural land, the capital city of Namibia experiences regular snake occurrence in and around houses, gardens and industrial sites. We investigated reported occurrences of snakes in the city over three years in order to assess possible temporal and spatial trends, and identified possible reasons for such trends. Between August 2015 and July 2018, 509 snakes of 17 species were removed from homes, gardens and industrial sites in the city. Puff adder (Bitis arietans) (32%,n = 163) and western barred spitting cobra (Naja nigricincta nigricincta) (27%,n = 135) dominated removal incidents. Of the other species, only brown house snake (Boaedon capensis) (11%,n = 57) and boomslang (Dispholidus typus viridis) (10%,n = 52) accounted for 10% and more of removals. The number of monthly reports ofB. arietansoccurrence showed a strong positive relationship with monthly total rainfall whileN. n. nigricinctapresented a moderately positive relationship with rainfall. The highest number of incidents were reported in January (18%,n = 92) when combining monthly data over the three years. Reports of snake occurrence incidents were highest in the affluent eastern and southern suburbs, possibly as a result of garden irrigation and larger open spaces between buildings, although the study could not measure whether reporting diligence was consistent across all suburbs. Although 76% (n = 388) of snake incidents involved venomous species, no snakebite incidents were reported during the period.

Automated summary

Wildlife is attracted to cities due to ecosystem services, leading to conflicts with human activities. In Windhoek, the capital of Namibia, encounters between people and snakes are common without reports of snakebite incidents.