No evidence of handling‐induced mortality in Serengeti's African wild dog population

Abstract

The disappearance of an endangered African wild dog population from Serengeti National Park (SNP) led to international debate centered around one question: were researchers to blame? The “Burrows' hypothesis” postulated that stress induced by research‐related immobilization and handling reactivated a latent rabies virus, eliminating the population. Insufficient data inhibited hypothesis testing, but since wild dogs persisted alongside SNP and have been studied since 2005, the hypothesis can be tested 25 years after its proposition. To be supported, wild dog immobilization interventions should have resulted in high mortality rates. However, 87.6% of 121 handled wild dogs (2006–2016) survived >12 months post‐handling. Some argued that viral reactivation would necessitate long‐term stress. Following immobilization, 67 animals were captured, transported, and held in a translocation enclosure. Despite the longer‐term stress, 95.5% survived >12 months. Furthermore, the stable number of wild dog packs in the ecosystem over the past decade, and lack of recolonization of SNP, strongly oppose Burrows' hypothesis. Instead, factors such as heightened levels of interspecific competition are likely to have contributed to the wild dog disappearance and subsequent avoidance of the Serengeti plains. Handling and radio telemetry are invaluable when studying elusive endangered species, yielding information pertinent to their conservation and management, and had no effect on Serengeti wild dog survival.

Spatial heterogeneity facilitates carnivore coexistence

“…In contrast, competitively inferior African wild dogs (Lycaon pictus) are subject to intense competition with lions, and adjust their spatial and temporal activities in response to lions (Mills and Gorman 1997, Darnell et al 2014, Swanson et al 2014. Lions are the largest contributors to wild dog mortality in free-ranging populations (Woodroffe and Ginsberg 1999), and have been the driving force behind local extinctions of wild dog populations (Swanson et al 2014, Jackson et al 2019. Wild dogs therefore spend considerable effort avoiding lions, including being active at times of day when lions are not Slotow 2009, Rasmussen andMacdonald 2012) and occupying habitats with inferior prey density but lower lion abundance (Mills and Gorman 1997, Marneweck et al 2019a.…”