Arboreal Duels in a Shared Niche : Direct Observations of Vinesnake (Thelotornis mossambicanus) (…)

ABSTRACT

Predator–prey interactions in three-dimensional arboreal habitats are among the most complex and least observed ecological processes in terrestrial ecosystems. Here we report two predation events of the Eastern Vinesnake (Thelotornis mossambicanus) on the Flap-necked Chameleon (Chamaeleo dilepis) in sand-forest habitat of the Zambezi Delta, Mozambique. These encounters document a clash between two contrasting arboreal specialist species: chameleons are ambush predators that rely on crypsis, panoramic vision, and ballistic tongue projection, while vinesnakes are active foragers employing stealth, elongate crypsis, and binocular vision for precise depth perception. Whereas the initial attacks were unobserved but most likely occurred in the arboreal milieu, venom-induced incapacitation or violent struggle dislodged both individuals from their perches, resulting in a shift from an arboreal, three-dimensional setting to a two-dimensional stage. These observations are the first published photographic documentation of Thelotornis mossambicanus consuming Chamaeleo dilepis in the field, and they reveal how even highly effective anti-predator adaptations can be circumvented by specialised predators. We discuss the phenomenon of vertical displacement as a consequence of arboreal predation and the value of direct observations versus stomach content analysis, and we propose integrating camera trapping with artificial intelligence-assisted video analysis as a promising approach for documenting rare arboreal interactions.