Beyond Venom and Constriction: Bite Performance and Trophic Ecology in the Genus Drymarchon

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  Beyond Venom and Constriction: Bite Performance and Trophic Ecology in the Genus Drymarchon Abstract Snakes exhibit extreme cranial kinesis that facilitates ingestion of prey with large cross-sectional area, but this ability is widely predicted to reduce bite performance due to decreased structural rigidity. Consequently, most large-bodied snakes rely on envenomation or constriction to subdue prey prior to ingestion. Species within the genus Drymarchon represent a notable exception: these large, non-venomous, non-constricting snakes routinely consume a wide range of prey, including large and potentially dangerous vertebrates, using only simple seizing and pinioning behaviors. Here, we quantify bite performance in three species of Drymarchon ( D. corais, D. couperi, and D. melanurus ), examine morphological predictors of biting performance, compare biting pressure to constriction pressure in similarly sized snakes, and synthesize dietary records across the genus. Our results sh...

Ecological and social contexts of scorpion stings in Manaus, the largest metropolis of the Brazilian Amazon

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Ecological and social contexts of scorpion stings in Manaus, the largest metropolis of the Brazilian Amazon

Abstract

Scorpion stings remain a significant public health problem in tropical regions, particularly in Brazil, where an estimatied 117,185 cases are reported annually, reflecting a persistent and growing burden on the healthcare system. Globally, more than two million cases occur each year, especially in areas undergoing environmental disturbances such as deforestation and unplanned urbanization. This study investigates the ecological and social contexts of scorpion stings in Manaus, the largest metropolis of the Brazilian Amazon. This qualitative study was conducted at the Dr. Heitor Vieira Dourado Tropical Medicine Foundation (FMT-HVD), a reference center for scorpion stings, between January 2020 and March 2025. Data were collected through clinical questionnaires, in-depth interviews, and household field observations. Thematic analysis was performed using Atlas.ti. Thirty participants from different age groups were included. Most cases were clinically mild. Five themes emerged from the qualitative analysis that address perceptions and reactions to the sting, environmental risk factors, post-accident behaviors, emotional impacts, and patient care pathways. Participants reported overlap between domestic spaces and forest fragments, limited knowledge about prevention, emotional distress, and barriers to accessing care, including late referrals and transportation difficulties. Scorpion stings in the Amazon are shaped by environmental, social, and structural factors. Integrated strategies involving environmental management, health education, urban planning, and improved healthcare access are essential to reduce their burden.
Benzaken, Z. S., Cristino, J. S., Benzaken, H., Sachett, J., Da Silva Carvalho, E., Da Silva Mendes, Y., Da Silva Pereira, H., Silva-Neto, A., Wen, F. H., Guerra, M. D. G. V. B., & Monteiro, W. (2026). Ecological and social contexts of scorpion stings in Manaus, the largest metropolis of the Brazilian Amazon. Toxicon, 278, 109122. https://doi.org/10.1016/j.toxicon.2026.109122